Schwintek says do not lube their slides, but I agree lubing them really helps.
Our bedroom slide works good but our large (Stove, 4 Door Refig, Microwave, Entertainment Center and Fireplace) Schwintek slide struggles in perfect conditions (Level, Shore Power and 2 Batteries at Full Power).
Keeping it clean and lubed in the tracks and in the rollers and gears in the wall have helped a lot.
Also something else I found was the power connections at the Schwintek controllers was poor and loose, I replaced the connectors with better connectors that have stayed tight.