I’ve had no trouble at all, Alex. No worries, they’ll get you taken care of, one way or another. They contacted ME after I posted here about the shipping being weird, and have followed up to make sure I got it as planned. They’re good people, no sweat. 
I just started installing mine last night. I did have to move the Z extrusion a little bit, it would appear that if you followed the Inventables instructions on extrusion placement (extrusion sitting right at the end of the T-nuts) you will need to move your extrusion upward about 1/16th of an inch. This is doable with all pieces mounted, and does not require a full tear-down of the Z axis, just some careful screwdriver work. I have chosen to completely remove the Z slide assembly from mine, though. Since I’m breaking the squaring anyway, this seems to be a golden opportunity to swap out the eccentric nuts on both the Z and the X carriage for the eccentric spacers and nylocks, as well as give the whole thing a really good cleaning.
EDIT: It just occurred to me that the variations we’re seeing here might well be on the Inventables end, instead of the Suckit design. There’s no particular reason that the length of that Z extrusion would have to be held to a tolerance tighter than .125" or so, and tighter tolerances mean higher prices for no benefit in performance at all, the function of the X-carve wouldn’t be improved in any way if it was held to a tight tolerance. So what we might be seeing here, at least partially, is just the tolerance range for the hole placements and Z extrusion lengths stacking up.
So far I have been very impressed, the quality of the workmanship on the boot is very nice. A couple of small burrs on the extrusion ends where it was cut that weren’t fully removed, but that’s being absurdly picky, and they don’t interfere with function at all. Not even exposed after assembly. I’m looking forward to getting it fully assembled and tested this evening! It’s FAR smaller and lighter than my KentCNC boot, so I have high hopes that it will cause less deflection on the X gantry!
I am most definitely going to have to change my clamping setup, though, there’s NO way the tiny brushes on this will clear the clamps I have now! I knew that going in, though, it just surprised me how much shorter the bristle is than my Kent setup. 'Course, it doesn’t have any reason to be long, given that its whole job is to just sit there and conform to the surface… So far, I’m really impressed! This is well-made hardware, and looks extremely functional.
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