In summary, in your opinion... Is it worth it?
That depends on a lot of things.
In my case, I went with the eGR, not eR9. I put it on my Poseidon gravel bike that came with Microshift Advent X. I really liked the frame, and once I got some of the fit pieces dialed in (bar, stem, and seat) and a decent pair of wheels, I was really very happy. People with these bikes sometimes swap to Microshift Sword parts for better looking brifters and more options for cassettes. But, you're still spending $160+ for brifters alone, and you're still stuck with mechanical brakes and a 10sp setup. The Advent X RD is not bad, but it does start to get less precise after a while and will need to be replaced sooner rather than later ($75+).
When the eGR went on sale for about $370 (I think is what I paid), I judged it to be worth a try. I get full hydraulic brakes, electronic shifting, better brifters with MUCH cleaner and easier routing, and I could slap it on my current 10sp setup and still have the option to easily transition to 11 or 12 speed in the near future. WORTH IT. About 500mi later and it's proven to have been a good buy. Brakes are excellent, routing is clean and nice looking, shifting is precise and fast (and still exactly as precise and fast at the 500mi mark as it was on the 1mi mark, which was not the case with Advent X), and I've had zero problems (so far). What's not to like? If it craps out on me and I can still claim a warranty and get a replacement RD, then I'll judge it still worth it. If I get to 1000mi or more and it craps out on me and I have to eat the cost of another RD, then I won't be super happy, but I won't be super upset, either. If it lasts me significantly more than 1000+ miles then it's all gravy, baby. Only time will tell from this point forward.
At 1.5x to 2x the cost of what I paid ($500 and up), my expectations would probably be different. What it's worth to you and what your expectations are for the price are yours to judge.
Wheeltop actually seems more serious (like opening a US office)...
Interesting. I didn't realize Wheeltop had targeted the US market. In fact, I thought they were specifically avoiding the US market and only selling in Europe and Asia.
I'm hopeful that Ltwoo will do okay. I noticed that Ltwoo is now providing OEM groupsets for all Walmart bikes. That's got to bring a pretty good influx of capital and a requirement for a certain base level of organization and supply chain management. Also, they've been more careful about avoiding patent infringements, whereas Wheeltop just decided to infringe on whatever they want and avoid the US market so as not to have to deal with that (at least, as far as I had previously heard).