It’s hardly worth listening to people who insist that there are no differences between speakers. It’s likely that most of them are people who buy an overpriced, sub-par product, get buyers remorse and claim it’s “jUsT aS gOoD”.
Depends on the source. If you’re listening to ***** material with a non EQ capable source; a house sound might sound better. This is generally where the hi-fi people sit; who argue about the esoterics of “warmth” and “bright” etc.
For cinema: We tend to just like something that can EQ well, to get us close to the source, blend well with the subs, etc. Movie soundtracks are (generally) recorded quite well, so we don’t need a house sound to flatter them. Just something that responds well to EQ and works well in-room. Sadly, a lot of speakers -even expensive ones- don’t.
My standard recommendation for movies is Arendal 1723 monitors. They’re very neutral. Very well-designed. Relatively cheap (as they distribute directly). But they’re obviously quite large.
Kef’s new upper-range speakers if you want to spend a bit more. Perlisten if you want to spend a bit more still.
For more discrete in-room installs; I like M&K (Perlisten also does in-walls; but they’re super expensive).
These are probably as neutral as it comes (without going down the Genelec/Studio monitor route).
Haven’t heard the XTZ cinema line or Ken Kreisel’s new stuff; but these are along the same lines.