This is Lego's fourth iteration of the Star Wars X-Wing Fighter (not including the mini-scale and Ultimate Collectors Series (UCS) versions). The first was #7140 in 1999 (reprised in 2002 with set #7142). Lego came out with set #4502 in 2003, and #6212 in 2006. The UCS kit, #7191, came out in 2000 and retailed for $150. [UCS are large and intricate, and are geared mainly toward collectors rather than for play.] This latest set arrived in January of 2012.
This latest version is, arguably, the best of the non-UCS versions. It is very much an evolution of 6212. Like the earlier set, it has working x-wings (they open and close using a gear at the rear of the craft), an opening cockpit, and retractable nose gear. Where the set differs is in the mini-figures and some key design features. The prior set included six mini-figures whereas this set includes only four: Luke, R2-D2, Porkins, and R5-D8. If you don't immediately recall Porkins, he was "Red Six" in Episode IV; during the final battle, he is the one screaming as his ship disintegrates around him. Porkins and R5-D8 are new mini-figures, and the droid sports a new conical top (as opposed to the usual spherical top of R2-D2 and the like). The design itself differs in a few big ways from 6212. First, the lower wings are now reversed so that the studs are upside down. This is what the UCS version did and it gives the model a cleaner look from the underside. Second, Lego reworked the wing folding mechanism and structure. This is important because set 6212's wings had a bad habit of breaking during play (due to how the rubber bands pulled against the bricks). Third, the engines and the guns are, I believe, more accurately rendered. The new set also has Proton torpedoes that attach to the fuselage. There are other small differences, such as the use of stickers rather than the printed tiles of 6212, and the droids now sit sideways, but these are distinctions that only catch the eye of hardcore Lego enthusiasts.
One small note regarding the build, you may find it easier for your child to activate the X-wings by only using two of the four rubber bands (the tradeoff being that the wings become floppy). This new model uses a different gear ratio than the old one, so while it takes fewer turns to open the wings, it requires more torque.
If you are a parent of a young Star Wars fan, it is hard to pass up this set. Yes, it is more expensive than many of the smaller sets (and there has been a ten dollar price appreciation over 6212) but, in terms of play, you get a lot of bang for the buck. The set is central to the original plot, so any movie scene staging is incomplete without it. Though my kids always want ALL the sets that Lego has ever made and ever will make, I've found it to be more economical to get a few of the key sets, even if they are more expensive, than to collect a lot of the lower priced and more peripheral sets. For a young kid, this set is an impressive build and has great playability. I do warn you, however, that these sets will suffer mechanical failures. Depending on the age of your child, you could become (as I have) a certified hyperdrive repair-person and obscure piece-finder (that became lost during an attack scene staged across three rooms).
If you are still unsure of the set, there are a large number of lengthy video reviews on youtube (search Lego 9493). It helps to see the set handled.