What kind of power are we talking about? Machine Vader was stronger physically and with the dark side than Anakin Vader. Do you think a normal person would have been able to pick up Palpatine and plunge him down the shaft of dread? It would take great strength to lift the Dark Lord of the Sith in the air and hold onto him so that he doesn't do a back flip into the air or force push you away from him.
It's an image worth pondering for a moment. Maybe, when you cut past the instrumental and songwriting virtuosity, the funny voices and characters, what is left is a man alone in his recording studio for days at a time.
I find it impossible to believe that Anakin is in his prime before he goes in the suit. He wasen't all that impressive actually in ROTS, and for someone who is supposed to be one of the strongest ever, he sure didn't look like it. I like to believe, even though the movie making technology didn't show it very well, that vader must be stronger in the suit in the OT's.
Remember, just because someone is physically handicapped, doesn't mean it has anything at all to do with his power. If that were the case, Yoda wouldn't be nearly as strong as he used to be right? But look at him, he hobbles his way around with a cane, barely walking, but kicks so much ass when he uses the force.
Mech vader could be the exact same way. Normally, he is slow, and has trouble breathing. But when he applies his full knowledge of the force which is obviously greater as he gets older, he becomes more powerful then he was before he went in the suit. I believe that his expanded knowledge of the force and extra training when he gets older far out weighs the physical limitations of the suit.
Mech vader is the strongest form. I mean ask yourself, do you think that Anakin in ROTS can stop blaster fire with his bare hand like mech vader did with Han?
I believe Lucas has said that Anakin pre-suit is stronger.
but i see what you mean ( i hate the blaster blocking with hand...) but many people hate midi's so whatever.
I think vader suit is more force powerful, but pre-suit his saber skills and agility are far superior. as well as his ability to hear the force pre-suit would be better, since he lost like 25% of his body, he lost 25% of his midi's. so the will of the force would be dimmer for him then it was in ROTS. however he would have more time to practice his abilities as he gets older. the thing is that had he not lost his limbs etc. he would have been 25% stronger then before (im just guessing the at the % of his body that was lost)