Skinny Pigs are born without hair except on their noses and feet. Their skin feels somewhat like soft rubber / velvet and can came in many different colors.
Baldwins are actually born with hair and loose it over a 6 week period of time. They then only have whiskers. They are the best for kids/adults with allergies but are also the most rare of the hairless guinea pigs. They tend to me more laid back than Skinny Pigs.