I am leery of the M3 with its glued grub screws holding in leaks (that factory "fix" doesn't say many good things about the company) and other reports, and the seemingly endless tuning.
I agree the grub screws with sealer is a half assed "fix" for the early batch with the holes that were drilled too deep, but if they use the correct sealer it should be good for the life of the gun. Unfortunately adhesives and sealers are sensitive to cleanliness, surface prep, and workmanship... And some leaked.
The grub screw decision probably came down to "grub screws and sealer and ship the first batch next week" or "scrap this batch, order more material, machine new lowers, then send off for anodizing and etching, and ship in 6-8 weeks."
Supposedly the issue is fixed on the later production guns and if your early rifle has a leak in that spot they'll replace the lower action block with a current production version and cover shipping both ways, so they are doing the right thing if you get a leaker.
I picked up an M3 today from the classifieds (been on the waiting list at Utah for 5 weeks, and after seeing that some people who ordered in early April are still waiting for theirs I jumped on the one posted this morning) so I guess I'll be finding out soon enough if the hype is justified. I just want an adjustable platform for shooting slugs and the M3 seemed be the logical option. My current .25 edgun R5M has been a very reliable rifle like all my other edguns (the R5M is matador #6 for me), but I can't find a slug that it likes.
I do expect the M3 to need a lot more fiddling and maintenance over time compared to the edgun, there are just so many more parts and o rings in the FX design. Sure, the M3 is very tunable and almost all adjustments are externally accessible, but that comes at the cost of a high parts count and lots of o rings and spots for leaks.
I'll have a better opinion on the M3 after it gets here and I play with it for a couple weeks. Given the demand and backorder list, if I don't like it I can probably sell it quickly.