[MixMasterLar]

I play both DDR and PiU. There are good and bad things about both:

DDR THE GOOD: 4 panels are easier to learn; The later arcade versions have alot of freakin' songs to play; The rating systems used are awesome and allow fans to keep score via Leagues and Online ranking; The Japanese Machines and SN2 allow memory cards and other forms of ranking; Picking songs is easy; BeForU.

DDR THE BAD: The charts have gone down hill since DDR 4th Mix, and took another dive at SuperNOVA. Later Mixes use alot of the same songs; Konami has never found one Timing Window they stuck with as far as Im aware of; Song selection is mostly Jpop with Speed Techno; The Dancing characters suck.

PIU THE GOOD: 5 Panels allow more flow in gameplay for advance dance players; Vast song selection with alot of genres and over two 3rds arnt just homebrewed; The newer charts are fun, challanging, and true to the song being played in must player's eyes; double chart counts as a regular chart thus meaning no paying extra for it; Later Mixes have alot of modes like Mission mode; BGs are mostly cool; BanYa.

PIU THE BAD: 5 Panels is hard for newbs; Only around 90 songs for most mixes; "Easy" charts arent really easy ie DDR and not all songs have easy charts to begin with; Hard to pick songs and mods and the method changes between some mixes; The old charts are offsync as hell and make no sense whatsoever (but in later mixes, they are restepped) Timeing window is HHHUUUUGGGEEEEEEE meaning it's mostly just passing the song. No real scores are kept.

I never played ITG, so I cant comment.

I like PiU's concept alot better (5 panels) but dang I like the score system in DDR a hella more and I do enjoy BeforU alot =)