Loc,
I have HWH slides on my coach, and it is a 1999 model. The front slide gasket is orginal (has never been changed) and the rear slide gasket was changed last year (it was nicked by a painter's grinding wheel).
The only problems that I have had is my bedroom slide lock and unlock solenoids needed to be changed. I believe the cost was about $200 each, and I changed them myself. I have owned the coach for 2 years, and I love the slides. No problems!
My opinion on slides is that electric slides (Valid) are better than HWH hydraulic slides, simply because with the latter you have the original of a hose leaking and damaging your coach interior. This is not possible with the electric slides. Also, if the slide room fails to retract with hydraulic slides it takes several men to push it back in. With the electric slides, if you disconnect the shaft one man can push it back in. It is mounted on ball bearings.
IMO, slides are like power windows in the 1960 automobiles, some people liked them and some didn't. But for all of the problems that electric windows gave, they are on virtuously every car on the market today!
Tuga & Karen Gaidry
2012 Honda Pilot