I never believed in 'slippery slopes' before, but this is a dangerous hobby, eh?
I had a couple statues from around '99, but I wasn't aware it was really an industry or hobby until much later. At that point, I was googling some of my favorite Marvel characters, and came across statues - and they blew my mind. VERY soon after, I found this forum, and PCS/Street Fighter, and that took over, as Street Fighter has been one of the most influential items/interests in my life.
Collecting philosophy? I made a list. All licenses, all characters in those licenses. Helps to avoid buying any old character that gets made into a kickass statue. PCS does it all the time to me. I'd buy a lot more if I didn't stick to the characters I absolutely love. The upcoming Bison Ultra that you're interested in, for example. That statue is awesome. I like Bison, but not enough to get the Ultra (in addition to the MM line, which I prefer). But it's a struggle.
Also tried to decide which characters I think have cool character design (so, good for a statue), versus which work better in a scene/theme (good for an art print). I tend to not like real world designs for statues. For example, I love Star Wars as much as anyone, but aside from Maul, I don't find the character designs particularly cool.
I started at about 1:6 scale, but quickly moved to 1:4 with Street Fighter, and prefer it for everything now by far. Perfect amount of detail and impressive size/presence for me. But I'm not rigid about it. If a character I want is produced from 1:3 - 1:6 scale, I'll consider it. I'd love to be disciplined enough to only own one statue of every character, but I just can't.
Good luck. I've been able to 'justify' spending more and more over the years. I'll reiterate my first point - this hobby is dangerous...