Hi Jack I've owned both and would say they are both quite different amps.
The AVI is a cracker but can seem a bit mechanical at times where as the Moon is much more fluid.
The AVI will drive just about any speaker however the Moon needs to be partnered with more efficent speakers due to it's 70w. Also the moon beats it on timing!
Again if you can get to demo the moon will need a couple of days switched on to sound its best.