OK, here goes...I am the originator of the Evert-it so I will tell you where it came
from and how we use it where I work.  We have a 60 bed postpartum floor and so see a
great variety of nipple shapes and sizes. I saw an article in JHL about using sawed
off syringes for mothers with flat or inverted nipples and decided to try it.  It
caught on within a week and the nurses found them so helpful they were clamoring for
more. I found them difficult to impossible to cut with regular scissors (one night my
son encountered me in my basement with a hacksaw...picture little plastic fragments
flying everywhere..as I tried to make a large batch of them).  That was not very
succesful and my next step was to take a box of syringes down to the maintainence
dept. and ask them to make me some.  On the way there, I encountered a colleague with
whom I entered into a discussion about the advisability of altering something and
using it for a purpose for which it was not intended (from a medical-legal
standpoint).  I decided if I couldn't do that, I would just have to make one of my
own!  Thus, the Evert-it was born.  I asked a friend who had a company, etc...the
rest is history.
In my experience with women postpartum, breast shells work over a period of days.
When one needs an infant to latch on it is not convenient to wait a few days. I
wanted an inexpensive device (one attraction of sawed off syringes) that were smaller
than a breast pump, could be used after the baby was awake and everyone was
positioned and ready for latch-on.  Also, the sawed off syringes were
one-size-fits-all and made of very hard plastic.  The nurses at my facility were
giving them out regardless of nipple size and so trauma was of concern to me.  The
Evert-it is made of a soft material to avoid that problem.  When we have used it
during engorgement, or in a mother with lots of colostrum, we cup feed the baby the
milk we get when using the Evert-it.  My experience has been very positive with
these.  There have been times when the nipple did not stay totally everted once the
device was removed, but we were able to achieve latch (when we hadn't been able to
before) because the nipple skin and surrounding tissue had been stretched and was
more pliable.
The nipplette really is used very differently and was designed for fairly permanent
correction of flat or inverted nipples.  My Scottish friend tells me that it "isn't
sexy" not to have nipples that don't protrude and that European women don't wear bras
like we do in the U.S. What do I know?  I hope this post helps.  Apologies for the
length.  If anyone has any questions please feel free to email me privately.
Edie Armstrong BSN, IBCLC, Fairfax, Va.