I consider myself a fighting game enthusiast. I spend probably way too much time on forums and sites like Shoryuken, Eventhubs, and Dream Cancel. I own an expensive arcade stick that my level of play probably doesn't justify me purchasing. I've been playing fighters seriously since Street Fighter Alpha 2. I'd only dabbled in KOF during those days, mainly the classic KOF '98. I've heard tons of great things about KOF XIII and decided to take the dive myself. I own and have sunk lots of time into all the big fighters of this generation: SSF4: AE 2012, Blazblue: CS (please note I haven't played EXTEND and don't really plan on getting it), UMVC3, and SF x Tk. In my opinion, KOF XIII is the single BEST fighting game of this generation, and I hope I can make a great case for you to check out this fantastic game.
First off, this game looks absolutely stunning. The "baboon hand" art style of the new Street Fighter games has always been divisive, and some people can get turned off by Blazblue's heavy anime feel (though that's a beautiful game as well objectively). The style of UMVC3, which is semi-borrowed from Tatsunoko Vs. Capcom, is pretty stunning as well, but if you're a fan of detailed 2-D, hand-drawn animation with TONS of character and personality, your eyes will feast on the amazing visuals in KOF XIII. There are over 30 characters here, all of whom represent different countries, styles, fighting styles, and body types. These SNK designs have stood the test of time, as characters like Kyo, K', and Iori seem, if anything, cooler and more stylish than ever. The backgrounds are generally great too, like a crowded London street with onlookers on double decker buses and a street market backdrop with massive 3-D elephants that blend in with the 2-D perfectly. There are SOME questionable ethnic stereotypes at play here, but that's a discussion for another day. As well, some of the onlookers get way too "animated," as the game speeds their fist pumps and claps up way too much to the point that it's sometimes distracting.
The most important thing about the visuals gameplay-wise is that powerful moves shake the screen and really look like they hurt. You FEEL the blows in this game, which is a credit to its presentation.
The music, which comes to you in a 4-disc soundtrack if you pre-ordered, is amazing as well, and endearingly old-school. You'll hear the same mix of crunchy guitar riffs and catchy synthesizers that have been the hallmark of this series for years. Note: I ordered the Xbox 360 version a few months after the game originally came out and STILL got the soundtrack, however I can't guarantee that if you buy the game now you'll still get it. I think your chances are better on 360 because it sold less on that platform.
The game has a variety of modes, including a Blazblue-ish "visual novel" story mode if you care about that kind of thing. Given that the "Ash Crimson Saga" was last touched upon in KOF XI on the Playstation 2, you might have already forgotten all about the whole "Ash is a very pretty man who is an enigmatic protagonist and can be good or evil" thing, so story mode is for hardcore KOF nerds more than a general audience. If you're just a fighting game nut, though, there are TONS of modes here, such as an Arcade mode with light story elements (all the characters have intros with each other), a Versus mode, a pretty robust practice mode with a variety of options, a variety of challenge modes like time attack and survival, color edit mode that unlocks more options as you play the game, a gallery that unlocks pictures and other things as you play, and what is my opinion the star of the show: the insanely hard Trials mode. Seriously guys, these trials, where you perform set combos with all characters that ramp up in difficulty, are freakin' brutal, the HARDEST of any fighter out right now. This segues right into my passion for this game: the trials are difficult but SO rewarding once you pull them off.
In my opinion, being a top-level player in any fighter is a difficult task that takes tons of muscle memory, practice, and skill. Where the rewarding difficulty lies in KOF is that timing and inputs have to be EXACT. The basic idea for combos is that, once you have meter, you cancel moves into each other. The way that works is that I can cancel a special move into a super move, but I input the super as soon as the first move hits. Seeing as how KOF has motions that aren't common in other games, such as two half circles back or combinations of diagonals and quarter circles, this is, in a word, freakin' hard.
Also, it feels damn awesome when you start to pull them off.
There are two meters in KOF XIII, one for canceling special moves and another for supers and EX moves, so meter management is huge in this game. Since you fight with a team of three, you can develop great strategies like using your first character as a "battery" to build meter, and pick your "anchor" character so that your last guy can take full advantage of meter. You can also enter a "custom combo" state once the HD meter, or "special move cancel meter," is full, and this allows you to pull off devastating combos by linking special move cancels for as long as the draining bar has meter left. Pulling these combos off is the meat of the game. I enter Hyper Drive mode, chain a combination of specials and normals together, and assuming I have super meter, I end the state by unleashing a super at the end. If I have lots of meter, I can even cancel a regular super into a level 3 "Neo Max" super. When you look at matches online with high-level players, you might think that the game is "broken" since you can effectively pull off close to 100% damage combos. However, I can assure you that you truly EARN all the damage you dish out in KOF. Nothing comes easy and that's a great thing for hardcore fighting fans.
KOF is a very fast-paced game and incredibly strategic. Matches are default at 60 seconds and most end way before that. You can dash, roll, jump, super jump, hop, and hyper hop in this game, which opens up tons of options in terms of spacing. You can also pull off guard counters that take up meter if you're getting pressured and have access to a "blowback" move that comes out sort of like a Focus Attack in SFIV. There's also a guard crush system so you can't just block all day.
Netplay is pretty decent, but not as smooth as something like Blazblue. As long as there's decent connections on both ends though, it won't be that much of a problem. There are absolutely NO game-breaking issues like SF x Tk's awful online though. Take note that there is also not a spectator mode, which is a bummer.
The last thing I'll say about KOF XIII is that, although there are still tiers in a sense, like for example Benimaru being a beast, the game is set up so that all characters give and receive the same damage. A big grappler like Daimon does the same damage to the schoolgirl Athena as he does to another big dude like Clark, and takes the same damage from Clark as Athena would. More than any other game right now, KOF XIII comes down to skill. I'll be honest, I still fairly suck at this game. But I put in the work everyday because it's the most fast-paced and rewarding fighter out there right now. For $40, you can't go wrong if you're a fighting game fan.
Note: In my opinion, because of the unorthodox inputs, this game is almost impossible to get the most out of with anything but a stick. That's just my personal opinion so if you're a diehard pad person, by all means give it a try and see if you can hang.