Experience with Stevens sump pumps?

[Yesnik49]

My local plumbing supply is pushing Stevens sump pumps, I am inclined to use a Zoeller n53 but I can't find a good piggyback switch locally. the supply guy likes the diaphram switch design that Stevens uses. I would like to get opinions on this.

also Stevens gives a 7 year warranty, Zoeller is one year. Seems that Zoeller could afford to offer a better warranty if their quality is as good as touted.