Guys thanks for sharing your SEI experince, and yes Rick that does answer my question. I realize that SEIs are bout half the cost of a new Merc drive and folks writing in are only the ones with issues. This was the second time this season I'd seen a posting about SEI ujoints being replaced under warranty amongst other issues. U joints aren't a big deal anyways.
Bulk of my experince is 40'hrs a year in fresh water, I guess I got luckily with my 1990 gen 1, in 25 years an input shaft seal and yoke, couple impellers, ujoints after 20 + years, a pair of gimbals, one bellows and shift cable... and a busted shift lever because a goon forced the drive on (me).
Sounds like the SEI is a good option if you need a drive. Thanks