Our first camper had no slide, it was fine. We now have 3 kids. We have one big slide and a lot more room. I wouldn't go back to a non-slide now. Being able to all sit inside in comfort when it rains, priceless. Being able to walk past each other to get from one end to the other, priceless.
Yes, there is minimal additional maintenance (lube the slide mechanism and the seals), and the additional cost *IF* it breaks... but it is worth the minimal risk. 20 years ago maybe slides were problematic, but they appear pretty straightforward now.
