In October, I switched from godaddy to namecheap. It took about 7 weeks to get 16 domains transfered. I left the others for dead. Its quite a process to move from godaddy, lots of unexplained transfer failures. But I'm feeling good that its done. Hope namecheap doesn't turn into a pain.
I switched to Moniker a few months ago. Moniker made it a very painless process. Most domains were transferred in a day (except for the ones that were less that 60 days old, once the 60 day hold was up they transferred automatically).