I have the luxery of having a good used audio store nearby. I was able to try some of these cheaper tube amps without too much sacrifice. My experience has been with the older, cheaper arc's and cj's and dynaco's is that they have more of the shortcomings and less of the strenghts of going tube, and are much more sensitive to matching speakers. Depending on what you are used to with your ss system, you may not get anywhere at all as far as enjoying an improvment, which takes the fun out of choosing tubes and maintaining the amps, which is a big part of going tube. (or MUCH bigger for older amps).
On the other hand, if you are willing to put in the effort, sometimes these super-low priced bargains can be made to sound surprisingly good and far exceed what is reasonable for the cost, but this takes more misses than successes.
I offer this further advice- take note that evan the more expensive tube amps require attention to system matching to have them perform the way everyone raves about when they recommend them. I would pay close attention to the speakers you are going to use and the preamp before getting any tube amp, and then you will be rewarded with the benifits of going tube.