In listening to the JA30s, keep in mind that the brands and types of tubes used can have a decided influence on the sound, especially the small input tubes (I prefer vintage Telefunkens, but others have their favorites as well). Since the 30s can use EL34s, KT88s and 6550s, that choice will also influence the tonal balance and bass response that you hear. Finally, you should try to listen to them with either your speakers or something similar in sensitivity, impedance and frequency range.
With respect to reliability, with the distributor and good repair shops nearby, I think you'll be fine. The only problem I had with my JA80s in my ten years with them was due to some modifications I had done to them, so I can't blame Jadis for that. The amp can eat up output tubes, though. I found that the best and longest lasting tubes in my JA80s were vintage Gold Lion KT88s; 6550s and EL34s tended to go bad and start blowing fuses after a year or so.
Overall, I found that when I first listened to the JA80s I bought there was nothing about them that really stood out and grabbed my attention, it was more a general feeling of "this sounds right". I think that if you get that feeling, then these amps may be the ones you should buy.
