Hi Sean,
SL deadlifts are quite different from regular deadlifts. Granted they do work the lower back as well as the hammies but if you don't feel it in your hammies THE NEXT DAY (not when you do them) then you're doing them wrong. IF done correctly, your hammies will kill the next day.
check the vid on this page for the correct form.
http://www.bodybuilding.com/fun/lance.htm#videos
I'm not saying that you're not doing them properly, but they are supposed to work the hammies moreso than the back.
Regular deadlifts definately work the back.
Take a while to get them to feel right cause they are worth it. If you end up still not liken em no matter just do some other hamstring exercise (setaed leg curls???).
Karl