Really?  No complaints other than the brusque attitude and continual underestimation of shipment dates.

No complaints about the frame here. Everything fitted well in my case. The only problem I had was with the groupset sensah/zrace which didn't work properly in combination with the frame. Since I switched to ultegra di2/hydraulic setup my bike works like a charm.
Of course I could argue with little complaints about missing rubber caps or minor paint imperfections here and there but there is nothing you could not solve yourself. Thats the price you pay if you start a project chinese road bike :-) Overall I'm more than happy with the outcome. Keep the fingers crossed there wont be a crack in the frame or something similar soon :-)

Hey fellow TT-X21 owners.  Quick question.

What did you do for the top cap.  I expected some kind of custom top cap to come with the bike because otherwise you are looking at the ugly clamp tightening bolt whenever you look down at the headset.  I have attached a pre-build picture for reference.

There was a top cap coming with my frame. There remains only a little hole above the clamp bolt. I will cover this hole with a little rubber plug later.

Don't set too much hope in these brakes. Especially with a completly inner cable routing like with the tt-x21 frame with sharp turns you won't get a braking performance close to a hydraulic setup.
If someone else achieves better results with this combination than me I'm interested to hear but for me the it was just not what I could accept.
I'm switching to shimano ultegra di2. Will be easier to route through the stem anyway :-)

I think its mostly due to the sharp angles the cables have to take in the integrated stem. But on the other hand even when pulled completely the braking power is far off a hydraulic system.
Sensah is cable only, so I have to switch the complete groupset. Was worth a try :-)
Still the frame looks like it has a very good quality...at least.

Yes its quite exactely the same setup as you have it  . Zrace cranks and brakes, sensah empire pro shifters and elite wheels. The zrace bb had a nasty cracking feel when turning, so i ordered a sram dub bb86 bb.