ARONOV LS-9100 ..How realible is this tube amp ?

Mine have been going strong since 97. I still play them most everyday. I did have one problem and that was a bad resistor in both of them. They were replaced maybe 10 years ago and no problems since. As far as service goes any good tech should be able to work on them. They are based on the Dynaco MK3. The reason I bought these were I heard them driving VR4's. That was a very good sounding setup. I think Aronov is up and running again.
http://www.theaudiobeat.com/news/aronov_la200.htm
If you have any questions I may be able to help.

Pescolar, The input impedance is 470k. As far as whether you should trade that is up to you. Can you audition them in your system? I would think they would go for $1800 on the low to $3000 on the high. When rolling tubes I find I like the Winged C, and my favorite is the EI KT90's type2. I have my amps moded to run in triode and thy sound great with the KT90's. Pay close attention to the driver tube. It makes as much difference as the output tubes. I like the RCA's and the IEC Mullards.