Water based polyurethane for exterior finish

[cmac2012]

I've been building a backyard gazebo for a client part time for a couple of years. He's a bit eccentric, the thing is way over built, or over designed anyway, but I'd like to finish it and have the pictures for my scrapbook.

He spent way too much money on mahogany doors and windows (it's enclosed) and the oil based polyurethane degrades in the sun way too quickly for my liking. Re-coating the thing every year is just not preferable.

The fellow at the local hardwood supply outlet swears that water based polyurethane lasts 4 or 5 years under UV before needing re-coating. I used it for some mahogany on a shower seat and floor grate in a bathroom that has no curb or curtain, the entire floor is the shower bottom and drain. Again, this was on his advice for longevity. That stuff has been in for a few months so I don't know yet about long term performance.

Anybody experienced with this stuff? It's sure nice to use.