The official forums for NBA 2K10 are currently in an uproar over issues being seen with NBA 2K10. Primarily the focus is on the framerate dropping in games and in My Player mode, along with poor online play performance or the inability to play online at all.
The framerate and online issues should not come as a surprise to 2K or consumers. Framerate slowdown has been pointed out in previews, reviews, my impressions, and user impressions across the web. Even 2K9 had trouble with keeping a consistent and smooth framerate especially in certain camera angles. Online play performance has been troubling with many 2K Sports titles the last two years. NBA 2K9 was sometimes playable oftentimes terrible, as the heavily promoted Team Up mode never even worked properly.
It is discouraging that problems in these two critical areas persist. Still it is only the first day and there is a chance that things will be cleaned up online wise and through a future patch. Past issues in these areas have not been completely fixed though which is certainly reason for concern.