I have an Alton, no problems with it. Very happy.
I'm afraid I had some bad experiences with dynamos. You do not want to find yourself suddenly in the dark on the M25 in the late evening. It happened to me twice!
I vowed to never have one on a bike again. I know its irrational, but I've had dynamos rebuilt twice and different regulator systems, still been let down by them...or other bits in the chain.
Still to each their own.
Cheers,
iain