Rock Band 2

Since I have both games, I'll highlight the differences. First off, I bought this primarily for my kids and I to play together (I have two daughters, 6 and 14 years old).

Since RB2 has no "strum only" mode, its difficulty levels are offset from those on GHWT (so Easy on RB2 is a bit harder than Beginner on GHWT, but easier than Easy on GHWT). Singing is the easiest of the parts to do (so my six year old usually does that), Bass guitar is (for most songs) next easiest, followed by lead guitar, and drumming is the hardest.

RB2 allows you to set up stand-ins for your computer-controlled players, so you can have the same band members when everyone isn't playing (for example, on very difficult songs my youngest will sit out, but I can still select "her" character as the singer, so she still feels like she's participating...also, we generally don't do the drums, but we can have the same character as our drummer, which gives us more of a band feel). There are several other subtle differences like this that give RB2 more of a roleplaying feel than GHWT.

Most importantly for those of us who are challenged in the area of manual dexterity, RB2 has a no-fail mode, which allows you to finish the song even if one of your members totally flubs it. If you're playing this as an occasional party game, or with young kids, that's very helpful.

In general, I'd say if you're more serious, looking primarily for a challenge and focused primarily on playing the guitar, GHWT is what you're looking for. If you're more into the atmosphere of creating a band, looking for a party game and something fun to do together in a family with members of different skill levels, RB2 is a better choice.

If you want to get both games (which I did), get the controllers for Guitar Hero, as they work for both games.

I managed to get my hands on Rock Band 2 a bit early, and spent the entirety of the evening playing. What a drastic improvement over Rock Band 1 on the Wii! This is identical to the Xbox 360/ PS3 versions of the game, and I was even more impressed than I anticipated. I was having a blast before I even had a chance to play a single note: The character creator tool was such a blast! You create a band and members, and then you hit the road. It was a really satisfying experience! This is really the first time that a Wii game has been truly competitive with other Next-Gen console games.

The World Tour mode is now available locally or online, and there are also challenges and battle-of-the-bands. There was a "Wii pre-release" battle available for the select few who managed to snag the game early, and I was able to compete head to head with other bands (there were only 3 other bands online since the game was not yet available @ most stores).
There are sure to be plenty of lengthy reviews, so I will just note some of my observations:

*Band Members - once you create your band-mates using the Character Creator, when you play a gig, there they are! I knew this feature was present, but I had no idea how exciting it would be the first time my character (who happens to look JUST LIKE ME!) appeared on stage! It was really satisfying! This feature was really well done. My first order of business was to create characters for my wife and all our friends. Whenever they come over and play from now on, they can use their characters. Also, these characters can be moved around, dropped etc. Also, whenever you select a character to play a gig with your band, they get a "cut", earning that character money which can be used to buy clothes, accessories, instruments, etc. Of course, my wife blew all her money on some designer jeans, some pink driving gloves, and some shoes before she even played one gig! Typical... =)

*Online - Some of the online features haven't been enabled yet, but I was able to play in the online battle of the bands. I was playing during a weather storm, and my internet connection was suffering. I had a hard time checking my email from my computer in fact! But, much to my surprise, the game chugged along, and I didn't see any problems with the online interface. The whole game is played "connected", so you don't have to keep logging on and off if you switch between local and online play. The interface was really polished and well done, unlike other Wii games that seem to tack on the online portion after the fact. A+++.

*Updated instruments - The new guitar and drum look and feel really good. The drums are sturdier, and also the pads are quieter. Other than that, not much of a change here, but I had no complaints about the previous generation of instruments.

*Music - This game seems to have a much more varied mix of music. Much like when I began playing RB1, I only knew a handful of the songs that I initially was able to play. A few of the songs that I initially played were somewhat familiar, but some were way off the radar for me. Still, what I have heard so far is great! As you may already know, there is a Music Store built in the game where you can use Wii points on your system to buy new songs, so there will be no shortage of great music to be played! I was also surprised to see that details about the band and even album art appear on the song selection screen. The interface is really clean and polished; it really doesn't feel like a "game" at all. There is really no end to this games replay value. There are already close to 500 songs available in the DLC catalog (and all of this will come to the Wii shortly), and new songs are added weekly. Guitar Hero: World Tour can't even begin to compete in this area!!!

Do yourself a favor and go buy this game. I loved RB1 on the Wii, and really didn't think I was missing out on much... as it turns out, the additional features in RB2 are really astounding! The solid gameplay of Rock Band 1 is there... the great music game is completely intact. RB2 adds the "Band" experience: Touring, Band-mate selection, losing fans if you quit a "set" prematurely, battle of the bands, never-ending amounts of fresh content to play, expansive leaderboards and band data, even the ability to order posters and figurines of your band!!! Rock Band 2 for the Wii delivers!!

Although Rock Band 1 for the Wii was a fun game, it was a huge disappointment compared to the other consoles. Have no fear, as Harmonix has made up for it with Rock Band 2!

PROs
+ Full World Tour. No more playing a straight list of songs. Choose from different cities and different venues in each city.
+ Huge improvements on the graphics. Rock Band 1 was a little rough to watch, but Rock Band 2 on the Wii is full motion and rendered in real-time. You can actually see your players instead of a static background movie.
+ Online Play! The game will automatically sign you in to the Nintendo WiFi connection and allow you take part in Online QuickPlay, Online World Tour, and Battle of the Bands. And, unlike Guitar Hero World Tour, you can play online against 4 other Wiis (GH:WT only connects a max of 2 Wiis)
+ Character Creator. Now you can actually choose and customize who you play as, with unlockable clothes, instruments, and more.
+ Compatible with Guitar Hero World Tour instruments and the Guitar Hero 3 guitar (and, of course, Rock Band 1 instruments)
+ DLC! The online music store wasn't available at launch, but will be coming in early 2009. The word on the street is that there will be 30 songs available at launch from the back catalog, as well as the same free 20 songs that were available on other consoles. Also, songs can be saved on an SD card (the Wii will accept a 2GB max SD card; otherwise, you only have 512MB onboard Wii memory)

CONs
- Still need to deal with Friend Codes if you want to add to your friends list (but that's not the game's fault, it's a Nintendo requirement)
- No tattoo creator... yeah, I'm sure that has a lot of people upset </sarcasm>

I purchased the disc only and used it with my Rock Band 1 instruments, so I can't comment on the new Rock Band 2 instruments. However, the Rock Band 2 fixes pretty much every complaint people had with Rock Band 1 on the Wii. The online play, DLC, and cross-instrument compatibility makes this a solid choice for every Wii owner's Christmas stocking this year.

UPDATE (1/13/09): The Wii Music Store is open and it was well worth the wait! As promised, the 20 free DLC songs are available, as well as 30 songs from the back-catalog. Songs can be transferred to a SD Card in about 5-10 seconds. I really haven't noticed any delay when loading a DLC song in-game. There are also sound previews in-game for DLC content (something Guitar Hero World Tour doesn't do). Songs are 200 Wii points to download -- equal to 2 dollars -- which is the same price as on other consoles.