The answer to this is you have put several amps on a shortlist and get to a place where you can try them. Your idea of the sound you want is different to mine which is different to the other guys. Feel is important too and you can't get that from a video. Frexample I love the SV but when I tried the Jub I knew in 10 seconds that it wasn't for me. Not saying it's a bad amp - loads of people love them. Just not for me and I went to the shop to buy one having read good reviews.