I still have an 06 Yellowstone double slide in addition to the new HOST 10.5' Cascade in my signature. I have not sold the old one yet. Emotional attachment I guess.
Slide Mechanisms are Powergear. Never an issue. Replaced refrigerator and heater. Always over that 12 years powered up and had it "ready to go".
I took my camper off the truck after every use (and I used it a lot) for over the 12 years of service. That is a lot of cycles on and off. Early on I never supported it on anything other than the jacks.
Put over 200K travel miles on it with many enjoyable and memorable trips. I also stored it outside in the weather. I had a leak in gutter area after about 9 years in spite of diligent efforts, repaired it and good to go.
I had some issues, some self imposed and some, I think due to the original aluminum fame design. HOST was an early leader in aluminum and double slides in truck campers. The frame design flexing when not supported off of the truck during slide operation coupled with the flexing due to the length of the camper and rear weight distribution, while traveling, were in my opinion early design deficiencies. However, static flexing and potential for slide binding were never an issue if the camper was on the truck or properly supported off of it.
My new Host camper's frame and structure is noticeably more ROBUST, especially off the truck than the older model.
I would recommend you put a support under the older unit when not on the truck because there will be more flexing of the frame otherwise.. I built a small table out of X'd sections of a single sheet of 3/4" plywood and carried it with me under the camper, in case I wanted to take the camper off when traveling. Easy to take flat pieces off truck bed and put under the camper when being removed.
I bought another HOST , so obviously I like the brand and their innovation.. You can check an older Yellowstone by looking at the lower front corner of the largest slide for evidence of filon cracking to check for prior flexing (frame cracking) issues.