Hi Kathleen B,  Medela has a pressure guage that they sell, but it is really
expensive.  I was able to borrow one, then we purchased a pressure guage at an
auto supply store and fixed it up to test the pressure of the pumps.  We
compared the two guages and marked our guage(which by the way was really
inexpensive) to be identical with the Medela guage.  The Medela guage was
really set up to test only the Classic, but when I was still a student at the
Lactation Institute I devised a method to check the pressure of the Lactinas,
as well.  Both on Medela's guage and the one that we use we see that the
pressure on the Lactinas is definately less than the Classic.  I do believe and
have had some moms tell me that they prefer one of these pumps over another, so
it is true that it often is a matter of preference.  As a rule of thumb, though
I find that the moms whose babies are in the NICU do so much better with a
Classic.  I really like Kathleen A's idea about complaining to the company
about the difference in cost to the pump rental depots.  Anyone else want to do
something about it?
Yaffa Stark, MA, IBCLC