The first chapter of Rurouni Kenshin is completely in color in my copy, and it's beautiful. Makes me wish the rest of all the volumes were color too.

I chose the second because for some art styles, such as the oe on colored pages of Yu Yu Hakusho, just threw me off. It's nice for a few pages, but the entire manga would be terrible. Otherwise I love color pages mucho 8D

I prefer the art to be mostly in black and white, but a color cover and first few pages is fine. Black and white is just much easier on the eyes in my opinion, plus it lets artists get away with more graphic content than if it was in color.

The coloured version of Akira that was done for the American market was awesome, but that was coloured by experts with enough time on their hands. Colour only works if it's done well, and it's hard to do this with the time and budget constraints. Plus many manga artists seem to be awkward with colour, probably because they have to rush it to meet deadlines, or they give it to an assistant to do, or they specialise in black and white; I've lost count of the series with great subtly shaded art inside and some gaudy weird-coloured painted-by-numbers picture on the front. It's pretty offputting having them on your bookshelf... Some american comics are just as bad, particularly older ones from when print technology wasn't so good.