I'm the same size and I like the large.
The bottom line is if you are not comfortable in the Medium then swap it out for a Large if you can, if you can't you will probably get used to the Medium.
5'10" puts you kind of between what specialized calls a Medium and a Large. Which one you ride is a personal preference. Technically by the charts 5'10" puts you on the top of the Medium size, but being 5'10" I prefer the large.deepsouth said:
The bottom line is if you are not comfortable in the Medium then swap it out for a Large if you can, if you can't you will probably get used to the Medium.