I currently own a V20. I went into two different T-Mobile stores. They both didn't have it on display and they had to bring it out from the backroom to show it. Sales guys didn't really know anything about it nor seem to care.
My first impression: gorgeous looking device, a lot better looking than the Note 8 or S8 Plus (or even iPhone 8's recycled design). It's also very light weight compared to the V20, slightly narrower and shorter (not super narrow like the S8 Plus). I'm very glad the curves were done right, not too curvy nor affecting usage. The back looks kinda weird though, glass looks a little warped.
Camera: I honestly didn't see any immediate difference with the camera quality and speed (compared to the V20) with the exception of the 13MP camera which looks awesome, the wide angle distortion is gone and quality is very good. I haven't gotten to really test it out as I was in the store playing with it for a minute, I think it does focus a little faster and has a better bokeh effect when taking pictures of objects close up.
Display: I also didn't see much difference with the V20's display and the V30's AMOLED screen, looks very similar. I'm sure it would look better in dim light since it's AMOLED. I think the P-AMOLED helped make the phone lighter since it's plastic and not glass.
If you already have the V20/G6, then maybe it's better to hold off till a price drop or wait for the G7/V40. Otherwise, I still think it's a MUCH better choice than the Pixel 2 and Note 8 personally, price wise and feature wise. If you have the extra cash this holiday season and willing to splurge, I'd say do it! Think I'm gonna wait a bit longer, at least until a very good tempered glass screen protector is released and see if there are any reports of issues (there's already reports of glass scratching easily, not surprised with Gorilla Glass 5).