Vandersteen 1c, and an integrated

Well, if the RM10 can drive them, I'd say that is a pretty hard amp to beat anywhere near the price, and about as maintenance free as a tube amp can be. Small, cool running, and cheap to retube -- in many years.

They YBA gear I have heard has been superb. Don't know about the particular stuff you are looking at, but they certainly have an excellent reputation.

The 60 Watt Rotel integrated is a classic starter combo with the 1C within your price range. But your other choices seem to be good ones as well; I think you'll be ok with any of the one's you list, but might want to add Arcam for consideration.

I'm a definitely in the tube camp, but I would discuss with Richard before going that route with the 1Cs. Most VS need a lot of tube power with current (not cheap) to shine in the bass region. I think the 1Cs have some nasty impedance dips in the bass region that could be a challenge to a tube amp; of course the midrange and above would sound better than SS IMHO, but I do think the speaker needs some careful matching to get the bass right. I have not tried the Cayin and Primaluna, so I'm not saying they wouldn't work.

Music Reference RM10 is a great little amp (I have owned the RM 10, RM 9 and now the RM 9 Special Edition). If the RM 10 can drive the VS it would indeed be a great, affordable set up, and I can vouch for the Pot-in-a-Box which I interchanged with my Joule 150 MK II which I preferred to Lamm, CAT, and Placette Active - in other words a $150 pre that competes with some heavy hitters. I'm still suprised that that a low power tube amp can make the best of the bass potential of the VS1s, but theory and listening are two different things. Hard to find the RM10 used though ($800-$1200 -MKI,MKII- when they do show up).