They are good foamers in hard water, but the best foam comes from those fatty acids in the C12 to C14 range (so lauric or myristic acid).
Sodium lauryl sulfate is in this category. (It has 12 carbons, so we know it comes from lauric acid). It very poorly tolerated by our skin - is is considered not so mild - and the irritation potential is quite high when compared to just about every other surfactant! It is normally used in combination with other, milder surfactants to make it less irritating to our skin. It is very easy to thicken SLS with salt, but you can use Crothix or glycol distearate (EZ Pearl) as well (and both of these are good moisturizers for your skin, so they will reduce the irritation potential).
You can find the lauryl sulfates with ammonium and magnesium ions as well. Of all the sulfates, ammonium is the least irritating, then sodium, then magnesium.
It is a great foamer and can boost the foam capability of other surfactants greatly.
As a disclaimer: I have never used SLS in any of my products, so I can't give you any formulation ideas. It's not because of the things we hear about them, but because I wasn't able to find it initially. I still don't use it because there are so many other less irritating surfactants than SLS.
SLS is used in many commercial formulations because it is inexpensive, offers great foaming, and can be thickened easily with salt. Something like Stepan's version of SLS (data bulletin here) is 29% active, and 10% can cause mild to moderate skin irritation. So using 35% or so of SLS in a product could cause skin irritation.
Please do not post a bunch of comments about how bad SLS is for you, how it can give you cancer, and how it is used to clean garage floors. I think we've established that it's not a great surfactant choice because of the high irritation potential. If you wish to leave a comment of this nature, please give me some links to studies that back your position that aren't from the EWG or Skin Deep sites. For more information about the myths of SLS, please visit snopes.com - it's a great site!
Join me tomorrow for fun with alkyl ether sulfates like SLeS!