My toy hauler used a cable driven BAL slide and both my truck campers have used Lippert's Power Gear mechanisms. None of these slides ever had problems and we camp over 75 nights a year. The most problems I read about are with Lippert's Schwintek mechanism getting out synch, so I have avoided units using this system.
My Ram 5500 has no suspension changes and handles the Mammoth well - It actually has a better ride with 6000 lbs of Host than with my previous 4000 lb Arctic Fox loaded. Everything I have read has owners of DRW 3500's still needing some suspension aids on 5000+ lb TC's. I was able to safely carry 4000 lbs on a F250 but it required upgrades to make it stable and reduce squat, so the same can be applied to a truck you already own - I would not buy a truck knowing I have to do this, but don't have a problem keeping an existing reliable truck and putting some upgrades into it.