Aspect ratio:
#1 is too narrow at 1:1 (482x478)
#2 is exactly as it should be, 1.33:1 (638x478)
#3 is also too narrow, 1.2:1 (574x482)
Black borders:
Why? They can be useful to trick Youtube's bitrate allocator, but as you don't even fill the screen, that's probably not what you had in mind. Also, in #3 you add one to the top while increasing the one already at the bottom.
Image quality:
#2 looks the best detail-wise, it seems to have suffered less than #1 from an intermediate compression step. They both suffer from failed deinterlacing though...
#3 has lost all detail, but that's an unavoidable side-effect of motion blur. It does look much smoother though.
IMO the tradeoffs in adding motion blur aren't worth it, but maybe that's just me. I may change my mind though if it can be somehow improved.