d, For bird houses and other outdoor items, you should consider a finishing nailer as opposed to brads. Brads are normally only 18 gauge (very thin), and have almost no head at all, yielding very little holding power out in the elements. Finishing nails are heavier (15 or 16 gauge) and have more of a head. Primary use for brads in bird house construction would be to hold the wood together while glue sets up ... and clamps will do that job better.

I have both brad & finish nailers, both Campbell-Hausfield, and they're okay. I don't use 'em a lot, but I have had them for 8 years or so, and total usage adds up to quite a bit. No problems with them.

You can get a stapler/brad gun that will shoot either type of fastener, but when you're using it to drive brads, the striker that pushes staples down will usually leave an elongated indention where it pushed the brad in. I don't have one of these combination tools, but have borrowed one from a friend, and noticed the indentions it made. In your situation, I'd go for a finish nailer and a separate stapler.

I've owned an 18 gauge Bostitch nailer for about 10 years and have had excellent service from it.