Sherri,
Welcome to LactNet!  I think the pump you're referring to is the one
manufactured by Bailey Medical Engineering, under two names (Nurture III and
Double-Up).  I carry both through my private practice and have worked with
100+ moms with this pump over the last year or so.  Only had two moms who had
problems with painful pumping, and nothing else worked for them either.
 These are great pumps for moms employed outside the home, who have a baby
keeping their supply going strong.  I never use these, though, with moms
whose babies are hospitalized and not nursing.  The difference in the pricing
has to do with one being sold as the pump and kit only, the other comes with
a carrying case, blue ice, and VCR tape instructions.
My opinion is that is it a great pump for an affordable price!

Kathy Parkes, RN, IBCLC
San Antonio, TX