Opinions - TD-125 vs MMF-7

I like vintage designs and I like TD-125, but it won't match quality of MMF-7 no matter what cartridge you're going to use.
Why don't you use both?
I use both modern Michell/technoarm with/Shelter 501 vintage Empire 698/AT 5001/Shure V15mxr.

I thought about it, but before I put $500-1000 in a second table, I'd sell the MMF and put all the $ toward a much better solo - like a used VPI Classic or Oracle Delphi (miss my old one), and get a cheaper vintage for the retro look to go with some vintage electronics I have.

Agree. Oracle Delphi will do better job than both you have.
Never had the chance to play with VPI Classic though.

I would think that a modded out 125 could and would out perform the mmf7. New plinth....New arm.....and an assortment of other tweaks will get you a stellar performer. I modded a 166 and liked it so much I sold my Well Tempered.

Rather than ask if the switch is a downgrade, why not ask what the differences are sonically and make up your own mind, rather than making it a pissing contest?

Having heard both, they are both fine decks. The 125 will be softer in attack, with less precision and a bit of conceit in the mid bass. You may find this richness addictive as it, roughly, replaces some of the bloom lost in the recording process, or you may find it an intolerable coloration. The treble of the 3009 will be a bit sweeter, or duller, depending on your perspective.

From a historical standpoint, if that matters, the 125 and 3009 are stone classics that will hold their value, or appreciate, in coming years and will probably require more maintenance as well.

If we want to start speaking about used Oracle Delphis, those will be in a completely different price bracket and the appropriate comparison in a vintage Thorens will be the TD-124 MKII.

Check out Vinyl Nirvana. They specialize in restoring Thorens. I bought a 125 mk2 with a new plinth & SME M2-9 I am extremely happy.