wait until their controler comes out, supposly seios dont handle the start and stop to well, low on torque, their controller doesnt stop the pump, but it slows it down using a frequency, and speeds it back up.
I ran a pair of M620s on a Wave strip for 7 months with no problems. Cleaned them once for coralline growth vs start stop problems others were talking about. Then there was a lengthy thread on RC about Seios, wavemakers and all the problems. Tamm talked about those controllers for a year now and that they would be out in Dec. '04. I wouldn't hold my breath on that.
Setup was taken down, but the two powerheads are still in continous use in different tanks for flow and no parts have needed replacement.