Nintendo 3DS News - I find it odd that the very first reviews give this game one star for reasons that are either misinformed, or at the very least, informed by a bias toward another aesthetic. For example, one review suggests that Arc System Works' Guilty Gear franchise is the paragon to which Capcom should aspire. The review goes on to suggest that the added content should have been in the original Street Fighter IV, but what's odd is that the Guilty Gear series is the very definition of "milking" a franchise--and this process continues with the Blazblue series. And the "missing moves" argument is equally questionable. Parries are systematized solely for SF3 series for a reason: The gameplay is designed around them, while SFIV focuses on, well. . . Focus moves. Introducing the entire myriad of all moves in past iterations would be like throwing every ingredient in the kitchen into the stew--it'd make a foul mess. Nintendo 3DS News
Another one star review suggests that the game is a direct port of the iphone App. As a long-time Street Fighter enthusiast and owner of both the iPhone app and the 3DS versions, I can say, authoritatively, that 3DS version is far superior in terms of graphics, features, and playability. Although it features static backgrounds, the game redeems itself through genuinely well-modeled polygonal characters that manage to resemble (if not duplicate) those in the console versions of the game. This is a feat in and of itself, given the complexity of the character models (and the robust character selection).
Alternatively, the iPhone app's characters are prerendered sprites and, while pleasing to the eye, pale noticeably in comparison to the 3DS version. The 3DS version also offers a new dynamic, over-the-shoulder mode that, while gimmicky, creates a new gameplay experience. Nintendo 3DS News
The 3DS version offers costumes, battle figures, and other extras lacking in the iDevice iteration. And there's the 3D, which is genuinely good--particularly when executed in the standard perspective: It adds tremendous depth and makes the characters appear like action figures come alive, duking it out in a dioarama.
While not ideal given only four face buttons on the 3DS, the buttons themselves lend an obvious intuitiveness to the game that's far more appealing (imho) that the unsatisfying mashing of a touch screen (one can use in the 3DS version, too, though the touch screen is primarily for beginners executing traditionally complex moves with a simple touch of the bottom screen).
For hardcore SSF4 players, the 3DS version is the best choice if you want to get a few rounds in on the go. Though it is $40, the game is a port of its console big brothers, bringing over 99% of the frames and accuracy of the hitboxes.
The 3DS will likely be hungry for software of a while--Nintendo is gearing up for big releases later this year like Kid Icarus and the Starfox and Zelda remakes. In the meantime, SSF4 is a great game to keep you busy. Nintendo 3DS Games are amazing.