What's the Porsche of hex keys, a set where some designer or engineer has really sweat the details?
Well, check out this 9-piece set from Wera Tools, which are color-coded by size, have abrasion-resistant etchings of the size in the handles, and also feature debossed size numbers in the carrying clip for redundancy's sake.
Wera finds that round handles "are better in the hand and make long and painless work possible," they write. "The plastic coating also ensures a comfortable grip, especially at low temperatures."
The non-sharply-faceted shape of their heads reducing rounding, they claim, while allowing "up to 20% higher torques" to be transmitted.
"The spherical output profile enables the tool axis to be deflected or pivoted relative to the screw axis, so that it is possible to screw around the corner, so to speak."
I'm sure these are cheaper in Germany, but 'Stateside these will set you back about fifty bucks.