Zelda owns.
It seems you have two points as to why MK is the "best".
1. He can recover from anywhere.
Well, so can Zelda. If you know how to use her B-special Tricks.
2. He is fast.
MK is definitely one of the fastest characters. Not in terms of running speed, but his sword is hard to get around.
One major problem with him, though, is that he has no projectiles. Zelda can spam Dins (not something I would do, or recommend), and some of her attacks are equally as fast as MKs. Plus she is a LOT stronger than him. Almost all of her moves have KO power, apart from n-air and d-tilt, and neutral B.
Honestly, there is no "best" character. Unless the same guy plays himself, there's no real way of knowing. An awesome Jiggs player could own an average MK.