http://www.laskoproducts.com/blower-fan-multi-purpose-pivoting-utility-fan-model-u12100/
These things are the absolute best for a small grow. They are smallish , have a built in speed controller and two electrical outlets. The fan exhaust pivots. They are quieter than any other fan I have tried and move about the same amount of air.
I swear by these things, I've got multiple but have only ever needed one which has been on 24/7 for 4 years and still works as good as the day I got it.
The flange for the ducting is only about a half inch, so that can get annoying as they aren't designed for this purpose. Once your ducting on and taped with some strong tape I haven't had one fall off.
These are the quietest fans I've tried. Not noticeable outside the room the grow is in, but inside you can definitely hear it.
Removing air from the tent is better than bringing air into the tent. If you have the fan setup as an exhaust it will remove the hot air from the tent and bring new air in passively from the room. It's almost always better to remove the heat than to try and cool it.