Last year for christmas I got a Dewalt 20v combo kit, I use these tools almost EVERY day. The drill included in this set seems to be REALLY efficent, but the secret to getting lots of holes on a single charge... Use a step bit.
Yes, bigger step bits are expensive, but they make excellent holes in plastic without cracking it. Much better than hole saws. If you don't mind waiting on shipping, cheaper ones off ebay or amazon will pay for themselves in time and frustration on the first use.