a DUAL turntable question...

I already have a DUAL CS-721 (luv it!) but the dum-dum in me wants one of each type, idler, direct and belt. Well the guy (EastCoastDual) that I bought my 721 from has two belt drives, a 522 and a 1257, both refurbed and are the same price. I googled and looked on www.dual-reference.com and all but I'm trying to find if one is superior than the other. They were even made in the same year. The only diff I can see is the 1257 has multi record ability (won't be used) and the 522 has the ultra low mass tonearm. Does anyone own either of these? Hows the sound?
I bought a CS-721 while in living in Germany back in the 70's. Loved that turntable. Then again I loved my Revox reel-to-reel too. Still have my Kenwood KT-8300 tuner from that time. Note to young: Just because stuff is old school doesn't mean it ain't good school.
The 600 series Duals, were the best belt driven tables. They had heavy two piece platters and were much more robust than their latter counterparts. The 1219/1229 are the ultimate in Dual idler driven tables. I use my 1229 every day, with a Grace 747 tone arm. Amazing table, my all time favorite.

The idler driven tables will have much more solid bass than either the belt drive or the direct drive tables. Also, pace and pitch are wonderful.