I think some people are being a tad over-simplistic.
If you currently have both Sky Q and Netflix you don't 'lose' watching in HDR or anything else.
You can still watch in HDR in exactly the same as you do now, using the app on your TV, or whatever. If you watch Marco Polo or Stranger Things in DV HDR now, you'll still be able to do so in exactly the same way once this goes live. The app you use now won't disappear.
But the vast majority of content on Netflix isn't HDR, and will be just as good watched via your Sky box, and a hell of a lot easier. Watching via the app will then be a bit more fiddly than on your Sky Q box, but no more so than it is at the moment.
Plans are afoot to launch HDR on Sky Q. Whilst some flavours of HDR may be seen as slightly superior to others, I really don't see any point in getting too wound up about getting one rather than the other. And, as I say, you can still get the original on your app if you want, anyway.
As for content...look, I have Sky Q for sport, and don't take the movies at the moment, as have so many Blu-ray Discs. However, I am thinking of including movies in my package, and have been looking into it.
The standard of content on offer if you subscribe to Sky Movies is hugely better than Netflix. It's not even close. Just going into the menu on my Sky Q box and seeing the number of 4K films available - both classics and recent - made my mouth water the last time I checked it out.
Ultimately, when this arrives, all it will mean for me is that I get Netflix more easily (most of the time), and possibly my monthly payments across the two platforms might be a couple of quid less a month - certainly no more. And anything I watch now, in whatever quality I watch it now, I'll still be able to watch later, in exactly the same way as I do now.
So nothing gets more expensive, more difficult, or worse quality. Some things get cheaper and less difficult.
What's not to like?
Reading some of the comments here you'd think the deal forced Netflix to stop broadcasting DV HDR altogether.
Unless I'm missing something? I'm always happy to have flaws in my argument pointed out.