I vote FOR sims. Sure, they can lead to bad habits but so can learning to fly without an experienced instructor. I started out with FMS then got the G2 sim as my son and I were building our LT-40 trainer.

We're not new to model aviation (both fly control line) but it does take a bit of time to get used to the orientation flying away and flying toward yourself. Taxiing and steering with the nosewheel also took a bit of practice.

Once we got out to the field and hooked up with a buddy box, we both soloed after about 6 buddy flights each.

The sim saved us a lot of time, balsawood and frustration on our instructor's part.