The original design of the Schwintek could handle the full wall slides. When Lippert got a hold of the system and started mass production...combined with the speed of install from the manufacturers, the system went to ****. I have the Schwintek system on three slides. I do have one giving me fits, but the nice thing about it, it is easy for you or I to replace, the whole system is about 50 lbs...thought the rollers under the slide are undersized and the screws holing the system together are of low quality...
Our last trailer had the BAL system on it...once again, very light and you or I can fix it if needed. The only problem, they are maintenance intensive. Whether they are in or out, there is always a set of cables under tension, which need to be adjusted every 90ish days or so. It is good to carry a crimping tool and cable ends, as they tend to brake off... I had to replace a motor on a slide, it took myself and a buddy about 30 minutes....then another hour for adjustment.
The older systems I don't think are very easy for the consumer to repair themselves.
Cale