Ordered an underfolder on the 12th, CFP email on the 13th, shipped on the 14th, and arrived on the 21st. Gonna shoot it this weekend. Some initial observations when I took it apart for a wipe and wood refinishing:
Folding of the butt. The butt is indeed folding, stays in place, and not loose.
Most parts are finely machined except the inside of the bolt carrier, which I frankly don't care because a) I don't see it and b) the cam lug will wear them smooth. The gas cup and pistons are flawless with even chrome lining. They move smoothly without lubricant. No burrs on the gas ports.
The upper handguard is in there TIGHT. Zero rattles. The dust cover, like most T81s, rattles under the rear sight block. A small segment of 3M adhesive fixed that.
The wood is fine. It's typical Chu wood (Chinese Catalpa) which is humidity resistant and flexible as far as hardwood goes, at the cost of weak surface hardness and prone to dings and scratches. The factory finish (felt like polyurethane), while not thick enough to eliminate dings, is scratch resistant enough that I'd give it a pass. I stripped it anyways as I'm not a fan of the near safety orange it displays under some light, but the finish on my wood are even with complete coverage. The upper and lower handguard fitment is great for a mass-produced service rifle.
EDIT: TI said it's German Beech not Catalpa.
If I had to nitpick something about the wood, it'd be the lower handguard. The rear end of the lower handguard had a 2-3mm gap to the receiver at a slight angle, not sure if it's standard across all rifles, but it really doesn't matter as it's secured by a screw therefore won't rattle at all. There's a tiny black overspray on the pistol grip but it wipes right off with some alcohol (and I'm refinishing it anyways). Again, not an issue for me.
The gun is as straight as (insert your favorite metaphor here). Straight barrel, straight trunnion, straight sights, straight everything. Intact finish on all surfaces except the bolt carrier guide rails, which are obviously scratched because that's its entire job, and the parkerized finish naturally won't hold up against the bolt cycling. Again, no faults here. The metal finish is a bit on the thin side as far as parkerizing goes, and a metal sling loop/button like my Type 56 sling could cause minor scratches if you rub it around a lot. I plan to use (and scratch up) this rifle a whole lot more, and won't cry over a mark or two for actually using the slings.
Folding of the butt. The underfolder clears the magazine. It does shift up and down by like 1-2 degrees if you move it by hand, but shouldering it properly and it stays put at one extreme of the movement. No side to side wobbles at all. The buttplate deploys and stows with some resistance so rest assured it'll stay in place and not flop around. The stock is fine for a chin weld and I actually prefer the slightly longer LOP of the folder versus my friend's fixed stock SE. I do prefer the side folding stocks and would be buying one of those if they ever gets imported again, but the underfolder is cool to have so why not.
I did add a tiny cushion to the tab on the buttplate so it won't create a crater in the lower handguard overnight. I also paracord wrapped the wire stock and it felt nicer.
The magazine well being tighter than the previous rifles I've handled (with a sample size of 7 including SA, SE, LMG, SR). The magazine doesn't drop free and it's harder to get it in. Did some light buffing on the sides of the magazines and it drops freely now when I tried to do the one-handed reload. I guess it's better to have it tight and break in than have it too loose. Some of my friend's magazine reinforcement "slabs" are polished to a sheen, maybe I should do that too.
The gas valve now ships on the 1 setting so people that don't read the manual would finally stop complaining their new rifle being a straight-pull. The clicks of the indents are tactile. You can see the small scratch caused by the sling's metal button.
I ordered a slant comp and it clicks in place fine. Slight rattle but it's not a precision muzzle brake nor will you hear it. It's fine. The left and right notches are, in theory, there to offset it slightly and compensate for left or right handed shooters. We'll see how it works. The bore is great and the crown is sharp.
On my bathroom scale it reads 9.25lbs or 4.2kg with the slant comp and an empty mag. The user manual said 3.9kg.
Overall I'd say my rifle is very well built. Our club have featured five different T81s in our previous events and every single one of them ran Chinese corrosives flawlessly, rain or snow, in the hands of countless first-time shooters. You damn well bet this T81M will join them.