Seriously...it's funny this comes up, because I'm giving this some thought at the moment.
Historically, I've heard that the only stuff worth using is real extract. And so historically, when I've bought vanilla, a real extract was the only acceptable choice. Brand didn't matter so much, although in relatively recent history, I've looked at ingredients. I prefer finding something with simple ingredient label. I think--but can't remember for sure--that I saw some cheap pure extracts that had corn syrup added. Or something added. I wanted just the pure stuff, thank you very much.
I haven't bought vanilla recently, but am considering it now. I might do some baking. I probably shouldn't--I really don't need the sugar. (Indeed, I make a point of trying to avoid sugar.) But it is the holiday season, and I keep contemplating baking one cake I remember from when I was growing up as part of my "celebration for one!" this year. But the problem is...my grocery budget is pretty low these days. I may well consider fake extract for the first time ever. Or possibly trying some other extract. We'll see what happens if I decide to bake, I guess.
This is only speculation, but I think one factor may be the nature of what one is baking. Some things may totally rely on vanilla (e.g., vanilla ice cream), and the quality of the vanilla probably makes a huge difference. Other things, vanilla probably doesn't matter as much.