I'm using Final Harbringer on my Sigma & Octanis combined with crit mods as well as the Berserker mod. Suffice to say, the attack speed get's quite high in the heat of battle. What bothers me greatly with this melee stance is the constant lunging that when combined with the quick attack speed more or less teleports me behind the enemies I'm trying hit. I get a few quick hits in and then suddenly I'm all the way across the room swinging at a wall or worse yet, plummeting into a pit. Turn around, try again and voila, face meets wall and the enemy is once more behind me and shooting me in the back.
This uncontrollable movement is a royal pain on maps that have a plentitude of pits because you are doomed to fly into them no matter what you do.
The lunging distance in some combat animations need to be toned down or be outright removed and instead be based on Warframe movement speed or something that gives the player better control. It's no fun using some melee weapons when I keep missing half the enemies due to uncontrollable lunging animations.