I have a SL8 from Yohobike and when I compare my frame to the X68, I am pretty sure that Yohobike and TanTan share the same manufactor. The bottom bracket on both frames is not even faced compared to the real one. Both seatposts have the identical seatpost with the grip texture at the bottom of it.
I am pretty happy with my frame and for the price I got it with the AliExpress coins + coupon code, I paid 549USD with shipping and no taxes, delivered by UPS (quite surprised about that).
The only downside that I have with YohoBike, it is not their frame but their lack of communication. Once you submit the payment, they act like submarine, disappear for few days, even a week and tell you « ok » and then disappear again. But based on the behavior of TanTan after the fork broke down, I think they are equal. Moreover, TanTan quoted 260$ for Ice Break paint, whereas Yohobike quoted me 100$.