Michael, the Durst M600 will do both 35mm and 6x6 formats. For 35mm only, the Valoy I or better yet the II or IIc will serve nicely.
The II is what I have and the IIc has a drawer for filters. PMCC is right about getting the negative carrier with the enlarger and if you get one that does not have the Anti-Newton glass, make sure it has the bronze/copper(?) condenser sleeve that slightly lifts the condenser off the negative to avoid A-N rings.
Make very sure there are NO scratches in the condenser as well.
Also make sure the enlarging lens extension tube is there and if there is no lens, the six element Nikor 50mm F2.8 has been mentioned as a good match for the Leitz.
Something I've noticed is the 75W bulb that some places sell for the Valoy is the same as the one for the Durst M600 but that's a longer neck bulb and IIRC, these were designed for a short necked light, like the one that came with my (second hand) Omega B66 Pro. Off-hand I'm not able to recall the nomenclature of what I believe should be the correct bulb but if you'd like I'll look latter this afternoon and post here. These are common enlarger bulbs and easy to come by.
If you do get a Valoy, you may pick up a bargain if the power cord has not been replaced yet. These are about the only thing that goes commonly wrong with this enlarger, as built, and the Leitz socket is VERY easy to rewire, something you may have to do when you get it home anyway.
You may also run across a Valoy with a replacement baseboard. If so, why not leave it behind to save on shipping weight/space and find something at home when it arrives. If you have a generous suitcase, you could fit the enlarger head and column into your checked luggage, though security will surely want a second look, another good reason for chucking a ratty cord.😛
I've mentioned elsewhere that my Valoy came without a board and I had a 3cm thick, polished granite slab tapped for the column base fixture. Now it is as steady and vibration free as, well, a rock, so... if you have to put a new board on whatever enlarger you get, think about granite, soapstone, whatever can be had flat, smooth, heavy and pierce-able, it'll solve the shakes for sure and might not cost much more than what you'll save by leaving the baseboard in the U.S., just don't drop the condenser or lens on it. 😉
Cheers