There is some controversy about the introduction of these guinea pigs to the pet industry. They were originally bred for laboratory research, and concerns about their immune system function and overall hardiness have been raised, though this appears to depend more upon their line and breeding rather than the fact that they are hairless. Through careful breeding, it is thought to be possible to produce hairless guinea pigs that are hardier than their ancestors (e.g. see Skinny Pig Origins by SphynxnCavies Caviary). As far as I can tell, there are/have been some lab strains of hairless guinea pigs with reduced immune function, it seems that it shouldn't be assumed that hairless strains should be any less hardy than their hairy counterparts.
Their care is much like that of other guinea pigs. However, lacking a coat they are a bit more sensitive to temperature extremes and must be protected from drafts as well as direct sunlight. They also tend to eat more to maintain their metabolism and body heat (an excellent quality diet is a necessity, but should be provided to all guinea pigs, hairless or not).
The following pages feature some photos which show the differences between the Skinny pigs and the Baldwins.