My preference has always been Snap-on, i find them hard to beat all-round. Cost is obviously something to consider, and they've got noticeably more expensive lately but i do find them generally the best (for me) in my use. The Dual-80s are all really good, lots of combinations in flex heads, handles, compact heads, etc. If i didn't use them for work i'd consider other brands but may well still choose Snap-on as overall i like them the most.
I have a Gearwrench 120XP ¼" flex head which is hard to beat for the money, it's very nice but unfortunately the spring for the retaining ball broke so it needs a rebuild kit. I recently got a ¼" Sata which appears identical and was even cheaper.
Since i started buying, cheaper options have become significantly better quality and other premium brands like Hazet and Koken have become more available too so there are even more options.
I got a few to choose from: