I use the living heck out of it. I'll say though, Lynn's marketing says "accurate enough for process work" and I haven't found that to be the case. Even before putting the carrier into the enlarger-carrier, complex masks can have alignment issues - I assume it's "great big pins" and only two of them vs. three, with one on a 2nd axis. But Alastair Ingless ain't selling his system any more! I've just learned to work with it, but it's a very nice tool for 120 and 4x5. I think for critical stuff, you almost have to go to a light table and pull the mask the right way and tape it down for critical alignment... I need a safelight-light-box I guess!
And you'll be handling your negs like nobody's business, so taking extreme care with scratches is a big deal - you can work with ortho-litho just like photo paper, like I'll cut a 2" scrap and just put it under the area I'm focusing on to dial in exposure and development, and then only punch and expose a full sheet when I have it dialed in - it's easy to scratch a neg with all that handling, I think in the future I'll try to get 2 similar negs of shots I'll be printing and use one for dialing in test pieces, and then have the "main" neg punched and ready for the actual masks. And your dust control game is big, a little dust on the neg becomes a big issue on the mask, though spotting can work in many cases - I advise a case of fine-point red sharpies! But you can bleach, spot-bleach, dodge and burn, make composite masks and so on. I'll try for "one mask that does the job of three" and stuff like that, it's a kinda fun mental challenge that does pay off.
And it's very nice to have a glass carrier that always returns to the same spot - even prints with no masking, I'll still punch the negs (well, you tape scrap film to one edge and punch it). Anyway, you're a methodical large-brained guy, I'll be interested to hear your experiences - obviously it's the kind of thing where you'll discover little workflow hacks and tips. Lynn has a Facebook group that's pretty active for masking, too.
The image below was really my torture-test, getting a sky behind that structure. The print below was baseboard masked with 16x20 ortho-litho, from a 6x7 neg. So far I've given up on really tight registration with Lynn's kit, he's also kind of scratched his head over it. But I am asking a lot of the setup I suppose. I have one more idea to try for tightening it up when I can get around to it. Not knocking it, it's kinda the only game in town right now and can give spectacular control for tonal expression, compositing gets a little tough. (some of the glow-ey artifacts are from lith printing vs. masking, too).