I try and gravitate towards Steam wherever I can, just for practical reasons. Steam runs all the time - I have to manually fire up any other game launcher. So I also have to bear in mind that any settings or changes I make to the Gamepass version will not carry over to Steam. There's even a risk that addons will be the same.
And right now I basically feel the same way, however I can't deny I've become rather excited by the whole prospect of this sim after watching so many videos. I could see me getting into this in a very big & expensive way in the future. I'm starting to compile a rather large list of places to go and things to do in this "game", once I earn my wings.
Time will tell on that, but I know that if I do, I'll regret not buying the Premium edition when I had the chance. Because as things stand, unless it runs like an absolute dog (and I don't think it will, my PC is OK), there's no question I won't be relying on the Gamepass rental and I will be buying this. It's even making me question my "no pre-ordering games ever" rule. That's saying something.