I ended up buying the ProMod -8. I would like to stretch 100 or so canvases before I give a review. But it has been working great so far and I will give an initial impression.
It was very easy to set up. The hoses have coloured tape on them, so you can't screw up. Mounting the universal mounts was easy but the directions were not the best, their video was clearer. Also the mounts could have been drilled different, they are drilled 2" deep so you can't just use a 2x10" to mount it to and the thumbscrew doesn't screw into the gallery stretcher T bar to secure it to the mounts. Dave was great to talk to, they paid for shipping which would have been about $500 CAD.
It doesn't take long to learn how to use it. You just have to be aware of your fingers are at all times. I found if I was feeding the canvas through the bars for it to grab onto, I would sometimes lift my foot off the pedal. Bad idea, I don't want to know what 40 PSI feels like pinching my finger. Also to make sure you leave extra canvas for it to stretch. It needs more than 1.5" past the stretcher bar, it is frustrating if you don't.
The Fasco stapler is ok. When stapling, it requires you to pull back a small safety lever with one finger and pull the trigger with another. Normally not a problem, but when you are using the stapler pointed up it's really awkward to do. The air needs to be just right to run it, too much and you will punch the staple right through the canvas. Not enough and sometimes it won't staple.
I agree with Dan Berg, the quality is excellent. Give me a few more months and I will make a video or two on it.