I have a 2015 377FLIK, It has the Stove/Oven, Microwave/Vent Hood, Refrigerator and Pantry in one of the 5 slide outs.
I have had no trouble with mine. The "House Type" refrigerator is loaded with food, the pantry is really loaded
with food (actually overloaded I'm sure).
The slide out works flawlessly, every time.
So, while the ones you looked at may have made noise and seamed to lack power, I think that maybe the unit wasn't sitting level when trying to put the slides out or something was blocking it.
They are also electric over hydraulic on mine, so this means that the pump will move 1 of the slides faster than the others until it's out, then it will move another one and so on. But, they are all moving while the switch is held, it just takes some time for the hydraulic pump to do it.
I do wish that each slide had it's own switch, but mine has a switch for each "upper deck" slide, then one switch for the 2 kitchen and master bedroom all combined. I have switches outside by the pump to stop the pump from doing 1 or 2 of the slides if needed.
When the dealer showed me my model, he didn't check to make sure everything was clear, one of the cabinet doors by the master bedroom slide was open and while opening it he destroyed the cabinet door and mirror that was in it...7 yrs bad luck for him I guess