I don't know of many under $5,000 SET amps, except the Elekit 300b amps. It comes either assembled or as a kit. I saw the instructions to the kit and the instructions are quite good and clear so I think anyone can build it if they have a little bit of experience with soldering, stripping wire, etc. I like the sound of that amp even though I am generally not a 300b fan.
I like low-powered tube amps, including SET amps. I own a pair of Audio Note Kageki (parallel SET using 2a3 tubes). But, many of my favorite low-powered tube amps are of the pushpull variety. If I were in the market for really nice low-powered amps, I would be looking at 6L6 or KT66 or EL84 pushpull amps as well as SET amps.