Brands are usually hit and miss. You can't really lump their products into disliking or liking them based on the products you've tried. Both brands have amazing products and products that aren't that good, and are constantly trying to come out with better products. A lot of times, brands use different labs to come out with a new product and will have them manufacture and release the products, based on word of mouth from the other brands they know, who have used them before. So, not all products end up being the same quality sometimes.
A prime example of this was the recent eye shadow palette release from Becca Cosmetics, a collab they did with Jaclyn Hill. They used a new lab that came very highly recommended from other makeup brands and sources, and the eye palette came out inconsistent. Some of them were perfect and everyone loved them. Then again, some of the people that got the palette found the eye shadows to be patchy and just not a good quality. So, Becca and Jaclyn agreed to recall the palettes, since she has the standards to not put her label on anything that isn't of the best quality. And that was just some of the eye shadow palettes that were released, not all. So, you can understand how some brands might have issues with their formula or the lab they use. That's not always the case of course, but it's just one of the many reasons it happens.
Like I said, Too Faced and Urban Decay both have good products to their name, like the Too Faced Chocolate Bar Palette, Chocolate Soleil Bronzer, Shadow Insurance and their Hangover Primer, to name a few. Urban Decay hit the mark with their setting sprays, Primer Potion, eye shadow singles and a lot of their palettes. Too Faced doesn't carry eye shadow singles, and a lot of the Urban Decay products, while of a good quality, aren't as well known as the Too Faced products. All in all, you can't really compare an entire brand to another. It's better to compare product to product. They both have their hits and misses, as every brand does!