EyeTV 3.0.2 has been great in my experience. I'd love it to have proper series recording (based on the IceTV series IDs), but apart from that I haven't noticed any issues causing the dreaded OS X beach ball. I don't use the Mac for anything else though, so it's pretty much just a clean Leopard install with EyeTV working away.
Please do report any issues to Elgato. They seen very keen on patching problems.