I can't speak to the plat 7, but I can to my short-lived experience with the plat 6. It came with me on two trips, and thanks to great return policy from where I bought it (along with a slight defect) I was able to give it back.

On the UA 319/320, it would only fit in the overhead by going in the awkward way of wheels up and out, making it hard to get in/out (or of course, horizontally, but I really hate to be that guy). This was near the front of the E+ cabin, though I've heard the bins are a little bigger toward the back due to the curvature of the plane. Also had it on a US flight (can't remember if it was a 319 or 320), and it didn't fit in at all except for horizontally. Never tried on a 737.

I ended up giving it back, because of the bin issue, but also because the handle to wheel it with was really stiff. I was going to see if I could take it in for repair, but then found out there was no where within 200 miles of where I live (CVG), so that cemented my decision to return it. I went back to Briggs, with a 19" transcend, and couldn't be happier. It's not quite as big, and more expensive, but definitely the Briggs quality and functunality, and I haven't met a bin it hasn't fit into.