I like them both!
! And as cheap as I'm seeing them on karaoke.com, you could probably AFFORD to have both!
they are created for seperate reasons, to be honest. The triple-tray is built to take advantage of the cd+g and VCD formats, and be able to have two other trays from which to load other singers. It's truly a machine that is embraced by the karaoke host community... but many people like it for a home player. If cds are placed in multiple trays, once a cd is finished playing, it moves on to the next available tray... in the right play mode. It also has a mode where it will stop playing after the selected track!
It will not play dvds.
The RSQ05 does all that, and plays dvds (mostly karaoke) as well... it will NOT play all commercial dvds (movies), however, as some of the later produced movies use some scripts that don't function with the RSQ. (I had trouble with the LOTRings movie load page on the dvd... couldn't see the menu items!) HOWEVER, for karaoke, it works just fine.
Matt
At first I thought about getting the DVD player, but after weighing the pro's and con's, I went witht the Triple tray. Originally, I thought "bummer, I won't be able to use DVD karaoke discs." 
Then after looking for songs, I found that just about any song I've looked for is available in CDG format. 
With ONE exception... Air Supply. 
(One of my all time favorites as well as that of my clientel) So now I'm looking for a way to buy the Air Supply DVD karaoke disc and copy it to either VCD or CDG format. 
Then life will be grand once more. 
So I'd say do what I did and weigh your pro's and con's and then choose. Maybe one day Pioneer will make a triple tray CDG/DVD player.