We did a slide and if I were to do it over, probably would not have done it, just because of the sheer size it takes up. I don't think it's "ugly", or an "eyesore". To me, its just a big ole slide, nothing too offensive, maybe not as particularly attractive like landscaping or some cabana, but its just a slide next to a pool. My kids are 9-18, (3 of them) and for the one day we used the pol this year, they probably were on the slide for half the time. They had a blast, and see them having a blast in the future with this with other friends and family over.
Yes, the slide was probably around $5k to add, a big chunk of change for one water feature. The cost is just another cost in the pool build for me. Everyone has to make their own personal choices on the validity of the cost vs. value, for me the value was there.
I do not have a particularly large backyard, and even with a 14x30 pool, plus the decking around it, I am right up against my easements so I did not have a lot of options on placement. If I had a bigger backyard, maybe a bigger pool, and maybe some more room to move the slide around it would not take up so much "real estate" on the decking, but this is where its at, and this is what we have.
For me, the decision to get a slide, or not get a slide is a personal one that needs to be thought through on many levels.
How much space will it take up? Is the high cost worth the value I think I will get out of it? What will my insurance costs be? How much use will I get? Does it "fit" with the backyard theme I am trying to achieve?
I say I would not do it again just because of the size and layout of my pool area. But if I built a bigger pool and had more space, the fun that it brings would make me think about all those things I mentioned earlier and "might" do it again. Just wouldn't do it in my particular setup.