[quote name='Zoglog']Singstar is both better and worse than Karoke rev. It's got the bonus of original tracks and music videos in the background (rather than those stupid ugly ass characters). However the tone tracking system in Karaoke rev is much better placed so that you can see and adjust and it's easier to follow the lyrics. Either way, both are great for parties, though mainstream people will definetly prefer singstar.[/QUOTE]
I totally agree, although I can't comment on the accuracy of SingStar, as I've only played UltraStar (PC emu). But as far as the interface, I definitely prefer KR for the reason you mentioned.
As far as I know, any USB mics (other than SingStar mics) will work with KR. I got two Logitech mics (made for PS2) on ebay for $15 total. SingStar ONLY accepts the SingStar mics.