The Vantare/Featherlite Cresco approach to slide seals was to put a flange on both the outside and the inside of the coach, and to have double (inner and outer) D-seal molding that the flanges would compress to keep out air/moisture/critters. The flange approach does not present the slick/clean lines that the use of a pneumatic inflatable seal does, but with the lack of compressed air, it DOES certainly remove the issue of seal ruptures. Vantare slides that were pre-02 (approx) utilized HWH hydraulics and two ram I-beams underneath the coach to move the slideroom in and out, and also hydraulic locking pins which engaged both with the room in and out. The only two major issues with the hydraulic system is that, on occasion, debris could prevent a valve from seating properly, letting hydraulic fluid to pressurize lines that weren't "supposed" to be pressurized...the worst case being the lock pin entend lines, causing the pins to protrude and puncture the outer skin of the slide room while the room was in operation. I have seen this on occasion. The other major issue is that of the synchronizing cylinder. If the cylinder was to fail, and the owner was not paying close attention upon extending or retracting the room, could get the room rams moving at an uneven speed and get the room lodged in the hole, possibly causing distorsion or damage to the room, the frame, or cabinetry inside the coach. This issue was uncommon, but happened a few times and was the prompting factor to Vantare's move to the twin electric motor setup. Bear in mind that while the "aftermarket" slides have some advantages over Prevost slides, they ALWAYS increased the weight of the coach by up to 1500lbs more than the equivalent Prevost slide. If you are considering buying a coach with slides, regardless of who did them, have the coach weighed on certified scales before you purchase. The coach may very well be overweight empty, especially if it was produced in the late 90's or this decade.
Hope this information helps.
Ben Cummings
Coach Worx