I've been playing Sky, and while I've been enjoying my time with it, I can see Robby's point. It's definitely not on the same level of Journey despite how much it's clearly drawing from it.
The main thing it has going for it over Journey is how much the social aspect has been expanded, which can be pretty great if you want to get in to that, but at the same time there was a lot of beauty in the simplicity of how Journey handled it. Otherwise, I appreciate that the environments are more diverse overall (with many being gorgeous in my book), I like some of the cosmetic options (though not so much the grind you have to do for it if you don't want to pay) and the flying feels good once you get the hang of it (and yes, getting the upgrades helps a LOT) - but yeah, it lacks the "something" that really makes Journey such a classic.
I think part of the problem is it's trying to both capture the wonder of Journey while still trying to be an ongoing multiplayer experience with cosmetics and seasonal events, and the two just don't quite gel together despite their best efforts. It feels like I'm either interacting with random people or playing through a solo experience at any given time, with only a few times where the two seem to blend together in cool ways. It's also a little weird that there's a linear "story" that you experience going through each of the realms, even though it's meant to be a game you go back to over and over again. So there's some parts of the game that touch on what made Journey so great, but then you'll likely skip over those parts when exploring more of those areas or spending time with other players, so even if your first playthrough is impactful (which it mostly was for me, actually), it loses something pretty quickly as you go back for daily missions or collectables.
What is kind of cool, though, is that I found some extra areas that were apparently where previous seasonal events took place, and some of those were pretty surprising and cool. That definitely helped return-visits, and if they continue adding areas like that I can see there being enough of an appeal to want to head back in every few months to see what was added. The current season is okay, though it weirdly breaks an already-kinda-loose role the game has by having straight-up dialogue. I can see why - its a collaboration based on a classic story - but while it was already weird seeing text boxes explaining things at the start of the game, having text boxes for dialogue for this one season was a little distracting at first.
I wouldn't say don't bother with it - it is free, and I've enjoyed my time despite my issues with it - but yeah, don't go in expecting it to be Journey 2.