Pneumatic or electric staple gun recommendations?

I would like some recommendations on pneumatic or electric staple guns that we can use to stretch canvases.

I have used manual staple guns for years for stretching canvases. We are talking about the thick Arrow brand staples made for this kind of work, not the flimsy ones similar to normal staples that people sometimes use to affix art packages into frames. The normal manual ones are hard on my employees hands. Some years ago I switched to the "backwards" style manual staplers, which are much easier to use. But they don't always hit the staple so hard, so often the staples do not penetrate the wood of the stretcher bar as deeply as I would like. And they break after about 18 months of use, and I have to buy another one for $20.

I bought an electric one from Bostitch. It lasted less than a year before it blew up into pieces (literally). It also did not drive the staples deep enough.

Suggestions? What brands do you use that you like? I know that there are a variety out there, and I'd like to get one that I can use for a long time to come that would drive the staples in better. Perhaps one of the "long nose" variety that I've seen.

Thanks,
John