My ratings are based around the niche it was designed for and "must have" involves what I must have. Previously I owned or shot with Canon 5D mk ii, 5D mk iii, 5D mk iv and 5DS. Compared to what I paid new for some of those, I felt the EOS R was worth every dime, even underpriced for what it gained for me. It's near-equal with a 5D mk iv minus one card slot. The EOS R lacked a few aspects, but excelled in others like the tilt screen, focus points and effectiveness with certain EF lenses. I found the controls and buttons better than any of the 5D bodies I used. Had there been a joystick, i would find use, but learned focusing on the touchscreen was ideal. The touchbar can be considered neither a plus or a minus. Since it can be turned off, it's more of a plus. I use the bar for ISO, and sometimes Kelvin.
Honestly I can say I wished the EOS R had more, but I still got what I expected and paid for. Amidst a an autumn 2017 cloud of confusion on the internet, what sold me was a review from Travis Harris .... the video linked below. His review also saved me selling my Canon EF 85mm 1.2 ii needlessly.
I have used EF and RF Canon glass, plus a few fairly recent Tamron lenses and they functioned perfectly adapted on the EOS R. The new RF 50mm 1.2 has been as good as the Zeiss Milvus I used to own, but with the added benefit of IS. But the EF glass adapts so good, there's little need to buy more RF glass. Any more RF glass would be a WANT purchase. Ergonomically, the body is excellent to hold. For weddings, it's my main camera with the 5DS used about 40%. The EOS R does what I want enough that I almost dipped into my next-body-fund to get another EOS R for a 3rd body. But I'm holding off a few months until a two-card body becomes available. I don't shoot 4K, but recently saw a Youtube review that virtually crucified crop-4K squabbles, where the man noted the sheer simplicity of picking the right lenses.
In the 8 months I've used the EOS R, I've never seen circles noted by other photographers. I learned it is apparently a firmware issue or problem with 3rd party lenses, and may be available to stop by disabling a lens correction / compensation from the menu. Oh .. the batteries last good. Near equal photos as a 5D mk iii or 5D mk iv. If the EOS R body CANNOT do what a photographer needs, then it's understandable why they would choose another body. Often, I find that the shortcoming is their own deficit. For example, the Fro Knows Photo guy Jared Polin originally nagged about the lack of joystick and means of focusing. Soon after, he did another review explaining he preferred using the screen of the EOS R. A complete reversal after learning and practice.