The fee to bring the amplifiers over to audition might be worth it if you can leave them in your system for a few days to get a sense of how they will sound in your system. The fact they will deduct it if you buy is fair in my opinion but I am a Pass owner, an Aleph 5, 60 watt per channel class A that sings devine with my Watt/Puppies.
Personally I would give it a shot, the only downside is you might want them and it is a big purchase but I have a feeling you will enjoy them quite a bit.