As an artist, I personally have a keen appreciation for black and white or greyscale comics.
In my social circles though, I have a lot of friends who qualify as peripheral comic readers, at best...and they generally have the same two thoughts about black and white comics.
One, they express a position that those comics look unfinished in comparison to the majority of the market.
Two, they represent a time period or economic state of the creator when color production was a step to be removed for cost reasons.
Now that's not to say either is always valid, especially when the creator makes the choice for artistic reasons, but it's a matter of perception depending on the position of the reader in regards to fandom.