I don't believe you'll find an answer to this. You'll only find more opinions. A cartridge change on the Technics will change qualities a turntable change will not and vice versa. If your friend doesn't listen for those qualities that come with a turntable change - does a DJ actually listen to how quiet a table is?, he'll never hear them. You'll still be right but he'll still want his new cartridge.

The 1200 has enough of a following that there are avid fans who support after-market mods and consider these tables to be quite Hi Fi.

KAB USA is a well known mod source.

Vinyl Asylum is a turntable enthusiast forum with many fans of the 1200.

I have an old SL 1700 that I play around with and the old Technics DD's can sound pretty OK.

Since you've already got the Technics, then I'd suggest staying with it and make some upgrades. Neither DD, rim-drive nor belt-drive is inherantly superior to the other. It's all about execution. The Technics SP10 MkII and MkIII are among the very best TTs ever made and knowledgeable audiophiles are scrapping their $20k+ belt drives in favor of the SP10. For everyone doing that, there's probably another music lover moving in the opposite direction.

You can gain a lot by moving up several steps in price range, but if you need to stay about where you are, then upgrading your Technics will give the most bang for the buck, IMHO.

Dave