I recently changed my reseller hosting from imhosted to Bliksemhosting.
There were some Cpanel issues (I think they were caused by the dns changes taking longer than expected - I was still seeing the Cpanel from imhosted), but I was very impressed by the support staff at Bliksemhosting.

One of their tech guys, Jave was a little argumentative, insisting it was a design problem, which I knew it wasn't, but even so, their response time was outstanding.
I eventually found the problem myself, but both Jave and Christina gave me a good feeling about changing to Bliksemhosting!

Incidentally, I changed from imhosted because their unscheduled downtime (7 support tickets in 6 weeks) cost me three resale customers, and their follow-up (sorry for the inconvenience but we have no idea how to prevent it from happeninig again . . .) was pitiful.