I'm not looking into a dedicated contact printing frame, but rather at a proof printer that can be used as a LF contact frame which will be the main use.
I understand they all serve the purpose well. Still there must be subtle differences among the three, like the clarity of glass, weight and construction quality. Any personal experience would be helpful.
I have the PrintFile version. It is well made and the glass is both clear, undistorted and heavy. I have, however, only used it for negative proofing, which it is excellent for.
I have two of the PrintFiles as well. Not saying they are better than the other ones, but they are way beyond adequate, and very convenient. Large enough too.
The glass is pretty hefty on it, and that fact combined with the foam keeps negs flat. Never had an issue with it. I understand the latch comment, but it isn't necessary.
If by chance the weight of the glass doesn't ensure that the contact is even, I expect it would be easy to add a simple spring clamp - essentially a large clothes pin.
I haven't ever needed that.
I have the Paterson and use it for 5x4 and 8x10 contacts and it works splendidly, the latch is solid enough that at first i thought i was going to break it
I have the PrintFile version. It is well made and the glass is both clear, undistorted and heavy. I have, however, only used it for negative proofing, which it is excellent for.
I have used the Paterson one on and off for years, using it for various things including 10" x 8" PAPER negs but will (hopefully) soon be trying it out with 10"x8" film. To date I have had no problems at all, so am very happy with it.