Electric is a little faster and easier. I use a manual pump because it was cheaper, and it's fine for my .40 and .60 size planes.

For starters, I can't tell much difference from one brand to the next. You don't need anything high torque for the smaller engines, but if you're planning to go to anything over 1.00 ci you might consider one of the stronger ones. I think Hobbico makes the Dynatron which has enough torque for the bigger engines.