Some impressions:
Captain Falcon: Looks alright. I hate the white stand, but he wouldn't be stable without it. In the ones I've seen, his shin guards and boots aren't completely gold as they have rusty brown streaks all over. The falcon emblem on his helmet is nice, so too is the decal on his back. The falcon emblems on his gloves, on the other hand, looks like the letter 'v'. His gun and its holster has smudgy painting. He has a dynamic pose and is one of the taller figures so far.
Little Mac: I've only seen two, but he looks great. Very simple design, but I like the little touches here and there like the edges of his singlet and the painted shoelaces. Like Cap, his pose is very dynamic and doesn't really fit with the wave 1 amiibo.
Pit: Probably the most detailed of wave 2 so be sure to check him out properly. I like the detailing of his wings, crown, sandals, and those things on his hands. In the packaging, a lot of the ones I've seen had marks here and there (mostly on his toga and wings). Upon opening the one I got, I was able to rub off a mark on his left wing. A fault in the Pit I got is that the design on his toga is about 90% consistent; there's an overlay of the gold skirting imposing on the design. His face is nice and he is taller than Captain Falcon (mainly because of the bow, wings, and stand).
Zelda: Zelda's ok. She's too blob-like for my liking, but she looks nice from afar. The detailing on her shoulder guards is mediocre and it's a bit disappointing that the top part of her dress merges with her skin instead of going over it. I like her braid though. Also, for you pervs, I'm kinda disappointed that they covered up the pants she wears underneath (there's no trace of it at all). All you can see are her boots.
Luigi: Probably the best amiibo of the bunch in terms of quality, but that's to be expected.
Diddy: Looks ok for the most part except for his derpy eyes.