Myles' Mechanic Guide

Not maxing it only takes away 4% HP being healed, and a few seconds of duration. It's useless in training because you have to sit to get its heal.

As far as metal fist mastery goes, I've yet to cease using both Atomic, and Flamethrower. Atomic has a taller range than Punch, is able to hit mobs behind you, and as far as I've seen about if not the same range in front of you as Punch. Flamethrower may not be incredibly strong but it's great for when you're training on mobs you still miss on (as I have since my early 70s). Once you get to fourth job though, I imagine Flamethrower will be completely useless. Drill, not so much. Drill is easily my most used skill. It creates the mobs for you to use Atomic/Punch, whatever on. The added damage from Metal Fist is certainly worth losing a very small amount of HP healed from a useless training skill, and very barely more used in bosses.

I believe it leaves around a 21 second cooldown opposed to the regular 5 second cooldown from maxing it. I don't think tapping the down key once (since you don't need to hold it down) hinders training much, but I'm looking at it in more of a boss perspective. Plus, as I said, after the restructuring it heals HP by 50% per tick.

Atomic Hammer is slower than Punch Launcher by 120ms, and has 150% less range (350% total vs. 500% total). Drill Rush, on the other hand, will probably always be used. However I doubt the 8% damage or so will be noticeable when no one will be using it to kill at such high levels.

Needless to say, Atomic Hammer's range gets nerfed to hell after The Restructuring, and Drill Hands gets a nerfed range, nerfed delay, and nerfed damage while Healing Bot only gets buffed. Since I'm not one of the users who will be quitting the mechanic once this update comes (aka, not just a bandwagon), I think Heal Bot is better in the long run.

EDIT: The cooldown for Level 16 after the Heal Bot disappears is 21 seconds, not 13. My mistake, though further proves my point.