Does anyone on this forum have experience with their 1x flat bar system?
Thanks

Yes. I put the 1x system on my wife's bike last year.

How has it been working, and under what conditions?

There was one thread on these where Wheeltop refused to warranty one that broke. So I suppose one of the disadvantages would be lack of support.

It was/is a pleasure to set up and adjust. Enter the number of gears and it was flawless. Change from a 10 speed cassette to 12 and change it in the app; done. Shifting is just as positive as mi Di2, maybe better.

It's been on light duty for little over a year, she mostly rides in Zwift and on MUPs...slowly.

The only negative I can think of is that the RD is heavy.

I have it, I wanted flatbar electric shifting as i have a mobility issue with my right hand that means the ergonomics of most shifters don't work for me. I wanted to keep 11spd and not have an enormous cassette (it's a commuter bike) so all the Shimano/Sram options went out the window. I run a bike shop so the relative affordability means little. I have had it since easter last year and aside from the app being less intuitive than the big brand versions it has worked flawlessly. I commute 22km a day 5 days a week, rode London to Paris on it and have charged it a handful of times. Anecdotally it is a lot quieter than Ultegra di2.Customers who have seen it on my bike in the shop have asked, but I cannot recommend it to them as a shop as you are on your own with it.