Some of my fondest memories are pre-mesh, even though I'm pretty young in SL terms. Having said that, I'd never go back to system feet. Or hands, for that matter.
I started out with mesh with Slink feet and a system body. Then Slink hands, still with a system body. Had that for a while. Now I'm full Slink Hourglass, but with a system head. Comfortable like that, and still haven't found a mesh head I like better. And I've demoed a bunch.
It was a gradual process for me. So I didn't find the learning curve very steep at all. It's still continuing, of course, but I'm comfortable where I am right now. So just take your time. Don't delete anything, you'll probably regret it.
Edit: Oh, and auto hide with the newest updates and clothing is just fantastic. So those just starting out now might actually have it easier than ever before.