If you could only carry one tension wrench what would it be? (i.e. serrated vs non-serrated, feather vs non-feather, twist vs no-twist, top-of-keyway vs normal, you get the idea)
For me it would be a custom (windshield wiper) double-sided non-serrated no-twist wrench for the bottom of the keyway with on side filed down for smaller keyways.
I prefer more rigid wrenchs due to the increased feedback even if it increases difficuly in applying constant pressure.
As a bonus if a lock is giving me a really hard time due to the wrench being double sided, I can hang a 1 oz counter-weight off the wrench to free up a hand.