Prior to buying our class C we rented various class c’s for 10 years. The units were slide and no-slide and ranged in length from 24 - 32 feet. Models included Sunseeker, Safari, Tioga, Coachmen, others.
When we were looking to buy we were aiming for a 26 foot 1-slide model as the best trade-off between space and maneuverability. We ended up with a 28-foot dual-slide model. The unit has been great with few issues. With 2 slides we have the square footage of a 32 foot no-slide model.
The 2 slides each have slide awnings that protrude beyond the ends of each slideout by 6-8 inches. This keeps all rain and debris off the top of the slide-out. If there is tree debris on top of the awnings I will “pop” the awnings from the underside with a broom to knock the debris off before sliding in. The rear slide blocks 2 drawers of the wardrobe cabinet. Other than that the RV is fully useable with the slides in. Below the rear slideout there is full width pass-through storage. This storage is great for holding a folding 6’ stepladder.
Powergear slide rails are on the bottom of the slideouts. I have seen RVs with slide rails on the sides of the slideout. I don’t know how the slideout seals can seal effectively over those slide rails.
Slideouts add weight. Just like people add performance parts to cars to improve the handling we have added thicker anti-sway bars, Bilstein shocks, and all-steel cased commercial tires to our “C”. With these performance parts our rig does not lean much through the curves and handles much like a large SUV.
I have not noticed significant air-leaks. There are inner and outer seals on both slide-outs. We have taken the rig up to ski areas in the spring and had cold weather and some snow. Would move the slides in after a couple of inches of snow accumulated to dump the snow off the slide awnings. Could also just operate with the slides in if necessary. Then the rig effectively becomes a no-slide unit.