Sheesh, I was trying to be vague so I wouldn't have to justify my opinion :D
I dislike spell slots and level based progression. I also think d20-based is the most boring dice-system, aside maybe from the very basic d100 "roll below your skill" (which is kind-of the same thing, but GMs keep forgetting to adjust the difficulty of the role). That is very much subjective and I understand that most people don't mind.
I appreciate the action economy, the very (VERY) well written rules - I am playing Shadowrun right now, and the editing and writing is atrocious - and I'd pick it over D&D any day.