I'll chime in here. I have the 13, 17, and 22 ft Werner ladders.
I'll never buy another, and that's because they changed the design. My 13ft Werner is the oldest, and hopefully it never dies, because I can't replace it. Here's why:
If you look at where the J hook pulls in and out to adjust the height on the newer ones, you'll see a blue plastic cap covering the end of the rung that the J hook attaches to. Under that J hook, the rung is badly tack welded onto the main body of the ladder. On my 17 and 22ft ladders, I have broken the weld on one of those rungs. They are still useable once the J-hook is locked into place, but I don't place much trust in them.
The 13ft one, on the other hand, has no blue plastic cap covering a ****** weld on the rung. Instead, they flattened the end of the rung, and double riveted it to the main body of the ladder. I've had that ladder for close to 10 years, and have beaten the snot out of it. When in extension mode, I adjust height on the wall, with me standing on it, by pulling the top J-hooks and readjusting. I suspect that's what led to the weld failure on the 17 and 22 ft models.
(And I can already hear you people saying "You're abusing it, you're not using it as intended!!!" And you would be correct. I abuse these ladders. When I got the 17 and 22ft models, I tested them by extending them all the way, leaning them against a wall at a 45 degree angle, climbing and standing on the rungs just above and below the main rotator joint, and jumping up and down on the rungs, effectively flexing the hell out of the main joint. I test ladders when new in a "worst case scenario" in a controlled enviroment, so that I know exactly what it will withstand, and what it won't.
All that being said, my 13 ft Werner, with the double riveted J-hook rung, hasn't led me down yet, and shows no signs of doing so. The newer models 17 and 22ft will be replaced with the same height Gorilla ladders when funds permit. I don't know the exact construction of the Gorilla ladders, but I did test one of the 26ft ones in a HD,(as far as I could get in an aisle before a HD employee stopped me, but I still got to do the full extension 45 degree angle test) and was impressed with its stability.
In closing, I'd vote for the Gorillas!