Only have a couple.
My first Smoktech VV Gripper's LED display and three front buttons fell into the
mod after 7 weeks of use, rendering it unusable. Luckily it had another week under the vendor's warranty, so I sent it back to the vendor and he returned a new one as an exchange. I've had this mod for several months, but I only use this now as a backup so it rarely gets used.
I was having a conversation with another customer at my local vape shop today, and he also had a ST VV Gripper. The same thing happened to his Gripper, the LED screen and buttons fell into his mod. His was out of warranty.

I also have an Segelei/Ovale V8 which is also now used only as a backup. It has worked flawlessly when used, although the battery compartment uses a wonky spring setup for the two 18350 batteries which makes installing batteries a PITA. Again, although I've had this mod for several months, it's rarely used.
95% of the time I use a Provari (USA made) or an iTaste MVP (first generation). The MVP has been working great for several months. I've had one Provari for about 15 months, and a second one for several months; both working flawlessly. I was recently gifted a third Provari.
I seriously doubt that I'll ever purchase another mod made in China. Comparison between them and a Provari in quality of build, workmanship and attention to detail, and durability are night and day. Most of the China-made mods use the 33.3 Hz chip, which I don't care for. Plus, China does not do repairs on their mods; they expect you to buy a new one. Provape gives a 1 year warranty, and thereafter will repair a Provari for as long as you own it for very reasonable costs and have it returned to you within a week. That, and the superior 800+ Hz chip are worth the added cost of a Provari.