The auto block function does not work at all.
It blocks when i dont want it too, such as in the middle of a stance combo, and when i do want it to block such as against knockdown abilities or the fishing line abilities (from scorpions and infested) it wont block.
Its very frustrating not being able to block on command, the result being stuck in an endless loop of being knocked down during stance combo's or stance combo's being cancelled by a block. It makes melee less fluid then it was before the introduction of phase 1.
What i do like is the seamless transition from gun to melee, and keeping the combo counter, i can close in on a group of enemies with my tombfinger kitgun, then as soon as i'm in melee range i can instantly switch to gram primes wide arc-swings.
On another note i think melee channelling needs a rework, ive hardly used it before phase 1, and im not using it after phase 1. I feel like the energy is better spent on warframe abilities, and the sacrifice of draining energy for more melee power doesnt feel very well balanced, channleing even more pointless if your using an exalted weapon.