In reply to tom_in_edinburgh: Out of interest, how are you using your Grigri? I find it very rarely sticks, especially the new one which should be good up to diameters of 11mm!
OP: I use either a BD ATC Guide or a Grigri 2. I pretty much always use a Grigri indoors, unless I'm doing lots of laps because it can get quite hot! ATC is always used outdoors, unless I'm sport climbing when I will normally use the Grigri.
For a new climber, I'd always recommend something like the Reverso 3 (Or you could wait for the Reverso 4 which will be out in Spring) or ATC Guide, they will teach you how to belay 'properly' and not rely on auto breaking. Also, they're more versatile, for example, they will allow you to belay in 'guide mode', which is fantastic when climbing multi-pitches and a useful skill to have. Buying something like the ATC or Reverso will mean you don't need to buy twice (ie. Upgrade in the future)
Mike