I went clipless years ago for my mountain bike and it was the single best upgrade I've ever made.

Despite what FarHorizon/Rivendell might claim, they feel far more efficient than toe clips. I'd previously toured on toe clips, and they didn't seem anywhere as good as clipless pedals. Toe clips seemed to offer minimal efficiencies and were both harder to get in and out of.

They also feel much more secure on bumpy offroad descents where my feet would otherwise be in danger of slipping off.

I have no problems disengaging when necessary- I've developed the reflex of disengaging when I think I might fall. Admittedly it's a bit of a weird reflex and maybe not everyone develops it.

The learning curve problem is also trivial. I fell off maybe 3 times because I forgot to disengage. However, this invariably happened when I was practising away from roads. Even if you stopped at a traffic light and fell, all the cars around you would have stopped as well.

If you want to make a gradual transition, you can get single sided clipless/platform pedals (I started on Shimano 343s). I quickly upgraded to Time Atacs because they're better in mud, offer good float and are dead simple and require minimal maintenance. I believe that the current pedal of popularity in the MTB world is the Eggbeater, which seems to have copied the design.