I own three Ashdown heads, two of which are older models, and I've never had a problem with any of them.
My friend owns the exact ABM IV 600 head that was at the bass show, and it sounds incredible. They shipped it the Monday after the show and he's had so many compliments from musicians and sound engineers at gigs on how good it sounds with his barefaced cab, ever since.
It's a very flexible amp and everything about it is very practical and sounds awesome. The EQ is just where you want them to be and it's got enough gain on tap to get a bit growly if you need it. Compressor and sub harmonics are all cracking too. I really love sitting and playing with it - even with the eq switched out, the amp sounds brilliant and has a very useable tone. It seems very reliable and has the usual Ashdown build quality.
Would buy one in a heartbeat if I had the cash, but I understand that the Ashdown sound isn't for everyone. Definitely worth a trip to try one out, don't think you'll be disappointed!