Try the Snap On! Although it doesn't look comfortable, it is!
I like these so much I have them in 3 different lengths now! Have done a lot of assembly work with them and they have lasted well! They keep your hand at a natural angle so are a pleasure to use, and have a decent hard handle too, so they don't pick up grit!
The only other one I'd advise is the PB 'Cross Handle' No. 255! Lovely tools to use and the ratchet is superb. Only downside is the pesky soft handle! If you're in a clean environment they're fine, otherwise, go for Snap On!
If you are not bothered about the ratchet, and just want something for hex bits, consider the hex bit drivers from KoKen or Facom! You will need one of each size, but they are not too badly priced! The Facom come with a nice free turning sleeve too! Very nice to use!