Problems? Barely anything significant enough to mention. The only downside not referenced in the video on the previous page is the fact that to really get the best out of Street Fighter IV you'll need to invest in an arcade stick, or Capcom's official pad at the very least. But having said that, even when partaking in the eldritch horrors of the 360's d-pad, things are a hell of a lot more acceptable than they were in HD Remix. And besides, control inputs are the fault of the console manufacturers, not the game.
And surprisingly, even the online play is decent. We feared game-killing lag, but so far we've found that fighting an opponent with a half-decent connection is almost the same as being in the same room. Slower connections mean slower play, naturally, but that slowness takes the form of an overall drop in tempo rather than any frame judder. And it's a really nice touch to be able to allow online players to jump in with a challenge as you play through arcade mode alone. Big old school respect points to Capcom for that.
Though to be fair, all of the above is a moot point, because frankly you shouldn't be playing Street Fighter IV online anyway. This game is all about sharing a couch and a TV with your friends; jostling, laughing and baiting each other over long nights spent learning, beating and relearning each other's tactics. Screw XBL, PSN, and the Wii. This is social gaming. But if you haven't got mates to hand, there's still plenty to do. With lengthy time trial and endurance modes included, as well as one of the most welcoming and complete training modes we've ever seen in a fighter, you're unlikely to be hit by the single-player blues at any point.
So yes. Street Fighter IV. It's the genuine article. The next true sequel in one of the greatest game series of all time. If you're foolish enough to have forgotten, it will remind you exactly why Street Fighter II changed everything in 1992, and if you haven't then it will be the next proper evolution of one of the rightful staples of your gaming career. It will be like playing SFII for the first time all over again, only with the years of love and experience you've since gained already built in. To long-term Street Fighter fans, everything old is new again. To the new players, we simply say welcome to the party. You're going to have a hell of a good time.
Soul Calibur IV? Yes. Soul Calibur is of course mightily accessible and simple to grasp itself, but the tighter focus of SFIV makes it a much more exciting and rewarding game. As great as it is, SCIV's combat now feels a little fluffy and imprecise after SFIV.
SSFIITHDR? Yes. As hard as it is for us to admit, after 16 years, Street Fighter IV has finally made it tough for us to go back to variants of SFII. Everything we love about Super Turbo HD is present in IV, but the latter is smoother, more flowing and, to put it bluntly, just contains more options for fun.
MK vs. DCU? Yes, yes, eight million times yes. There's no contest between the Street Fighter's finely honed, exhilarating depth and Mortal Kombat's stiff, gimmicky silliness. Never has been, never will be.