I find the Ashdown to be more of the tone I like. The lightweight head is nice to have, but going from playing an SVT head for 10+ years, the ashdown isn't "heavy" IMO.
But since it's a backup head, tone isn't my number one goal. I'm more concerned with reliability. It's the head I leave at the practice space, my gigging head says home with me.
Also, the Genz might be easier to get rid of on the forum. They seem to be more desired than Ashdowns, and it still has a transferable warranty on it.
I'm leaning on keeping the Ashdown, but I like to hear what people have to say on the forum. More often than not, you people bring up things I never considered. I have a weird feeling in my belly about selling the Genz, I dunno why