Mega Man is indisputably my #2 guy now. I absolutely love his playstyle. The only things I have a problem with are:
1) Hard to kill reliably.
2) Crash Bomb and Leaf Shield are virtually useless.
Metal Blade is more useful than any B move in this entire game. That's a fact. It's every bit as abusable and useful as it was in Mega Man 2 - comparatively better than any other weapon in the game and incredibly viable against most of the game's opponents.
My one problem with Mega Man is that, at high percents, I find it hard to land a solid kill. His Bair can miss the vital hit. Now they know I'm going for it and will defend and punish accordingly. That leaves me with FSmash, DSmash, USmash, BThrow (150% or more), and if I'm lucky, Uair. His Bair is really good if I can land a walk-off stage spike, but beyond that, everyone knows which attacks are coming, and they're very punishable.
The BEST thing I've learned lately is that USmash can be jump-canceled and used out of shield. This means I can use it as a counterattack or even a viable edgeguard.
The other thing is that Side B and Down B are hardly useful for anything. Side B comes out slowly and is not only easy to avoid, but can be used against me. Down B doesn't have much use for damage or defense. It does only 1% if you grab someone, doesn't do much damage, and comes out slowly. Even if you're using it and not throwing Leaf Shield, you can still get hit.
I'm hoping to address these problems in the future because I really want to be an awesome Mega Man.