Any amp that matches with the wilson line would do well
I have heard that the VAC Avatar works nicely with the JR's (in fact, if I recall
correctly Albert showed the JR's with the Avatar at one of the electronics
shows in the last two years). I'm sure the BAT integrated would be nice as
well. Those are both tube units of course.
As for SS. I used the MAC 6900 integrated for 2 years with my JR's and
thought it a great match.