Here is my take on slides, decide how you plan on using the trailer. I personally will never spend the money or want the extra weight of a slide because the only thing we do with our trailers is sleep in them, and I do not need a slide while I am snoring.
We are always on the go, hiking,biking,canoeing,playing,shopping,etc etc to spend anytime in the trailer.
and meals are always cooked on the BBQ
If it is raining we are playing games under the awning or enjoying the campfire under a tarp.
but I guarantee you I am a dying breed of "RV'ER"
I guess I am a "camper" and love every second of it.
But if you plan on hauling your trailer hundreds of miles and spending between 35-70 dollars a night then sitting in your trailer for hours on end, yeah, get slides.
Goodluck