Here are my findings so far. I have the ffp FML-4 reticle.
First, the issue I had with the tube diameter was mostly an error on my part.
@Denys was right, it's quite difficult to take a good measure while the scope is mounted. After removing it from the mount, I measured it at 34.07mm. Some error could still be involved, lets say it's on the bigger side of specs. It was wedging in in a M-Brace mount, but fits perfect in Spuhr or MDT rings. So that's a non-issue really.
Now that's out of the way, here's what I think of it optically.
Eye placement is critical to get a really sharp image. If I put my eye slightly off center in the side to side plane, the image gets blurry. It's quite sharp though when my eye is very well centered.
Diopter adjustment is a bit of a problem. If I use the trick I mentionned in an ealier post, my eye gets tired relatively quickly at lower mag. I'd say it's best to adjust it at the mag you'll mostly use, and accept it wont be perfect all the way through mag range. Personnally I use it mostly at 8-10x, and that's where I adjust the diopter now.
I went with the FML-4 instead of the dual because of a personnal preference. I'm not a big fan of trees. I don't like having the tree hanging below the amiming point at low mag. If you like trees, I think the dual would be a better option. I find the FML-4 quite good at low mag. But from 6-7x and up, the ring gets crazy big. It's not translucent like on some lpvo and it takes a lot of place in the field of view. Also, there's no marks before 2 mils. The inside of the ring is 1 mil, the outside 1½. That's not very hepful for wind holds. If I have to dial, or aim at a "random" spot upwind, I can do that with a sfp. In my view, the ring should be translucent and the .2 marks should extend all the way toward center.
If March eventually makes a new ffp reticle for it with .2 marks from center, I would send it for a replacement. .2 marks are very usable at 15x.
That said, the way I use it, mostly at 8-10x, I would have been better with the sfp 30mm version. The ffp gives me nothing more on that scope. I think I was too much attracted by the turrets and the 34mm tube.
.5 marks are still usable for wind holds, so the new dual is still a very good option I think, if you like trees.
Mechanically, the scope seems to be near perfect. The turrets are very good. The way they lock is just perfect, even if I pretty much never lock them
Something to note, on MY scope, there's a bit of image jump when changing direction in magnification adjustment. It's not uncommon and dosen't bother me at all. I know some people would not tolerate it, but really it's small and has no impact on usability.
The big pros are still the size and weight of this scope, and its apparent robustness.
If you ask me if I would buy it again, here's my answer :
No, I would buy the 30mm sfp version.
Hope it helps.