Although I hear alot of people who "worry" about kitchen connections in slides, I have seldom if ever read reports of actual problems with them. Ours does indeed house the kitchen sink, stove, microwave and dinette (not the fridge), and we have not had a single issue with water lines, drain lines, gas lines, or electrical lines. Since it is now 16 years old, I assume that it would have had issues with those lines by now if it was prone to them. The slide mechanism itself (HWH Hydraulic, both slides and jacks) has also been trouble free, although it does have a way to manually retract them.
4X4van, Many of the owners like yourself do not have issues with flex connections in slides. :) However, there are some people that have and the info is out there in the owners forums documenting it.
a couple of mechanics and even a salesman steered me away, so I listened. But, like yourself, they work fine for many people.
My close friend used to say to me "if you ever buy one of those, don't bring it to me to fix" So I never bought one. :E
What I have learned while hanging out taking up space in my friends rv repair shop, when we do have issues regarding this , the fixes are normally easy due to inexpensive plastic collars and fittings, you just have to be physically able to crawl down there and do it and not be impaired by an injury. These things always let go when we are camping using it, never when its sitting in the driving, right ? :)
there are many posts and videos out there for info:
https://www.forestriverforums.com/forums/f229/propane-lines-and-plumbing-in-the-slideouts-152644.htmlhttps://www.rv.net/forum/index.cfm/fuseaction/thread/tid/22394147/print/true.cfm