I own Arrow Video's Deep Red in the standard edition Blu-ray, which includes only the full-length domestic cut, meaning if you choose to watch it in English (the speaking language of many of the main characters), there are random scenes which are not dubbed in English, because only the slightly shorter International cut was done in English at all.
After learning all of this information I caved and ordered Arrow's 2-disc 4K set of Deep Red, which includes both the Domestic and International cuts in 4K.
In my opinion, Arrow shouldn't be forcing their customers to choose between the broad compatibility of Blu-ray and the relatively significantly smaller compatibility of 4K Blu-ray. Most disc labels will include a standard Blu-ray disc in their 4K sets, but Arrow seems to only do this very rarely (the only one I could find on their site as of now is a limited edition steelbook of Silent Running, but once it sells out customers will again have to choose between a 4K or a blu-ray). Arrow, for the most part, releases a very fancy 4K set, then a normal 4K release, and then a standard Blu-ray release, all separate releases one must choose from. If one wants a "complete" set, you'll usually have to buy the same film multiple times. Unless you don't really care. I usually don't most of the time and will just buy the Blu-ray for compatibility and price, but rare circumstances like this come up where I'm actually missing significant content by not owning their releases multiple times...
At the same time, I've gotten annoyed enough with one of the 4K-only releases I bought - Lucio Fulci's Zombie from Blue Underground - that I went back and bought the standard Blu-ray release of the same film. This is an odd inverse case to Arrow - with Blue Underground, if you buy the 4K, you'll get a standard box containing a 4K disc and a Special Features Blu-ray. But if you go for the Blu-ray release, while there is a plain one that's otherwise identical to the 4K release, there's also a fancy 3-Disc Limited Edition that includes a blu-ray, the same Special Features Blu-ray, A CD of the soundtrack, a fancy thick booklet of essays on the film, and it all comes in a fancy thick box with reversible cover art and a lenticular slipcover. Like, geez, Blue Underground really seems to be treating their 4K customers like crap by not offering any of that in a 4K release. From what I've seen this has been the case with their releases of Zombie, The House By The Cemetery, Maniac, and Manhattan Baby. It's bizarre.
But then, Blue Underground is a bizarre company in general, even in the boutique Blu-ray landscape. The last time I tried going to their own website, they were only selling like maybe half of their current releases on it, and the website was one of the jankiest I've used - somehow jankier than Synapse's website, which is saying something.
I already own Blue Underground's 3-Disc Blu-ray set of The House by the Cemetery, and it already looks stunning. But I've heard really good things about the 4K... So I might... eventually, maybe also double-dip on that one.
In non-boutique news, however, I've been eyeing the Superman 4K box set which collects, Superman 1-4 and the Donner Cut of 2 all on 4K and Blu-ray (see? The big guys know to include standard blu's, even if it's just repressings of the same discs from 2011), but I watched a video where a guy pointed out the 2011 box set those standard blu's come from also included an extra Blu of the "Extended Edition" of the first Superman, which is like 3 hours instead of 2½ or something, and Superman Returns, and an entire extra disc of just bonus features.
That's a lot to miss out on for the 4Ks... So watch me double dip on that too! 🤪
Eventually I'm just gonna own 3-4 different releases of every movie in my collection and when people see it they'll ask if I need therapy
oh also the 4K of Suspiria because if ever there was a movie that would benefit from having a higher color gamut and HDR it would be goddamn motherfucking Suspiria