The one thing to watch for: you usually want it to say "regulated" power. Hum can (but not necessarily will) result from 'unregulated'. Some RS units are, some are not regulated. But as stated above, higher ratings are just fine.
The higher mA units can power multiple pedals via daisy chain cords. If you think you may end up with a Rock and/or Roll pedalboard with a bunch of stomp boxes, the higher current ratings could come in handy.[This message was edited by Jon Light on 07 August 2005 at 03:40 PM.]