Retractable hardtops have been around in the SLK since 98 and they work extremely well. I own a 280K mile M3 98 vert and frankly it functions just as well as my E93 does. However the problem that usually causes issues with E36/46 is the top itself. When is gets worn the material stretches, the tension straps also stretch and just plain wear out. The E93 has interior headliner with strings as well and some have already replaced their strings to keep the top operating correctly.
There is not much real new technology and the reason the hardtops that retract work well is that the hardtop itself is not prone to wear out. It will eventually wear out bushings and bearing but that will be a while.
If you keep your top, headliner and tension straps in good working order you will most likely not incur any issues. I have owned E30, multiple E36 tops and none including the 280K mile top have had issues.
Once the top get jacked up too many people have no clue what to do or how to fix the top. That and most technicians are not trained to work on these tops nor are many upholstery shops. That means many times a simple problem turns into a total mess when individuals experiment...