Me + my buddy play as a duo. We both attempt singing; I'm keyboards; he's drums. Most of our pop-covers "dance" spot is done with us playing over, around and with midi files.

Works fine if you can live with the technical constraints already mentioned (such as fixed length [unless you get good with A-B looping], pre-progammed "feel").

The other negative point when starting from zero is that in trawling the web for midi-files you will discover that you normally get what you pay for; the free ones that are available are free because no-one would pay the money for the &&&& that is being offered. There are exceptions but not very often.

I sometimes use web-sourced midi files as startpoints but there is almost always a lot of re-writing and remixing required - sometimes I wonder whether the original transcriber was using a different song! Sometimes this is requied to the extent that it would probably have been better and quicker to do the entire thing from scratch!

In comparison the commercial offerings out there (Tune 1000 for example) are usually usable after very little twiddling; my major tweak is to run them through Michael Bedesem's (sorry if the spelling is wrong!) "MidiPlayer" program which does a fine job of adjustimg voices and volumes to suit my PSR3000.

By the way, you can put lyrics into "normal" midi files; you don't need to use the XF enhancements to accomplish this and so far I've found support for the XF extras to be very limited.

Hope this helps

John