MAC's foundations, as another poster has said, can cause horrible things on the skin, which is why I love Clinique for foundations and powders: they give me great looking skin without breaking me out - you have to choose the right one though for your skin type. I think their skincare line is absolutely horrific for my sensitive skin though, which is ironic considering the whole "we're allergen-free!" thing.
Clinique Eyeshadows can be either perfect if you want a subtle look (like me and using a MAC Shadestick in Beige-ing underneath works absolutely amazing for them) or horrible if you have no primer and expect dramatic results and high pigmentation. They are not like MAC eyeshadows at all: more like DIOR with even less pigmentation haha
I got some cheap Stila eyeshadows at Nordstrom Rack and absolutely love them, but Stila pressed powder smells horrible and doesn't do a thing. I don't like their lipglosses so much either.
CHANEL has the worst foundation ever. It smells like house paint and, as you can imagine, gave me incredibly bad breakouts.
Too Faced's shadow insurance is good and so is their eyeshadow & makeup brushes, but their packaging is so incredibly cheap and really just quite lousy.
I love Benefit's lipsticks because they're so moisturizing, but Benefit is perhaps the worst for being overpriced, focusing so much on their packaging and not their actual products. Erase Paste is perhaps the worst sticky mess of a concealer I've ever tried in my LIFE, and their other weird pseudo-foundations, what are they called, Boi-Ing and Get Gorgeous? Same deal as the Erase Paste. Yuck.
This thread is really useful and I'm loving reading everyone's responses <3