Yes. It holds the film flat enough for the apertures I'm likely to use with the lenses I have, operates smoothly, is in good registration with the groundglass viewer, and doesn't show any light leaks. It's not a substitute for a 617 back on a 5x7" camera or even the half-darkslide trick that I use on the 8x10" camera, but it extends the range of what I can do with a 4x5" camera (which is what I've been carrying lately for travel), so it looks like something I'll use. I don't own any other 6x9 or 6x12 back for 4x5" (though I do have 6x6 and 6x7), so I might use it occasionally for those formats, say, if I'm shooting mainly 4x5" B&W and want the option to shoot some color rollfilm. For the amount of 6x17 I think I'll be shooting, a simple $500 back is fine for me. If I decide that I REALLY like panoramic formats, I'd look into a 7x17" camera before looking into one of the more costly 617cm options.
I think I'll get a 75mm lens with more coverage than the one I have, so I'll be able to use it with this back, and maybe I'll see if I can find one that can share a center filter, at least for the time being, with the 90/8.0 Super-Angulon.