My Armory Profile
I am a level 52 warrior using the 2H Fury spec in the sticky. I installed Quartz timer so as to work the Slam with my slow 2H weapon. My play style is solo PVE. I've tanked an instance just once, a PUG for ZF. According to the group, whom I told in advance was my first time so that there were no hurt feelings should I suck, I did very well - likely the result of getting great advice from guild tanks (my main is an epic 70 hunter) and having seen it done well (and badly) enough times from that perspective to have at least a small clue.
I've used defensive stance three times, once while tanking and twice when I accidentally pulled multiple adds grinding and switched to defensive stance and a sword-and-board combination with an "oh, crap!" macro I had built for just that contingency.
I have never used Berserker Stance. I've never felt as though it has slowed me down in levelling. I guess my only gripe would be that I find myself often having to bandage or eat between mobs while grinding, but from what I've read here that's more of a talent spec issue than a stance issue (i.e. prot spec requires less downtime between mobs than fury spec).
Am I wrong for sticking with battle stance 99% of the time? Is my perception faulty, and could I be levelling significantly faster by varying my stances?