Parents might consider trying out EyeToy: Play with their children before investing in Groove, being that the latter is not a series of mini-games, but a stand-alone game that requires a greater focus of time attention.
Creative gamers can design their own dance routines in a special mode, and will also enjoy freestyle breaks in which they can cut loose accompanied by a variety of visual effects.
Fans of rhythm/action games who especially enjoy waving their arms in the air should also consider Para Para Paradise, either in the arcade or the much rarer home version (be prepared to import or eBay this one.) The two games are similar in concept, though Groove is far less intricate.
Drunken party guests who can overlook Groove's faults will probably be the ones to enjoy it the most. They'll also like the soundtrack, all inoffensive party-friendly numbers from the likes of Jamiroquai, Jessica Simpson, Madonna, and the Village People.
Deaf and hard of hearing gamers should have little trouble following along based on visual cues.