in your opinion who makes the best AR uppers and lowers?

Hello all searching for an 8-10.5 upper but have never ordered components and put together so not too familiar with companies and the quality they offer. No I don't want a 16" or 14.5 but I do want a LEGAL build. Not the most familiar with SBR and pistol differences besides something about 26" OAL. Also leaning towards an aero lower with brace if anyone has experiences with them please chime in. Budget is not a concern it will be used for training and lots of range time. Any and all experiences or opinions will be appreciated.