I have an S1, 3 wheel push trolley, that I have kept since also getting an electric trolley. Very solid, easy to put up and take down. The front wheel can be tweaked to make sure it wheels straight, very handy if required. You can add a scorecard holder, drinks and umbrella holder via the motocaddy system.
Not the smallest in the boot but then it is an older model that has been superseded by more compact versions. If that was an issue I guess you would be looking at them.
I can't compare against the powakaddy model but I have no qualms in saying the motocaddy is a good trolley to have.
FW3S here, folds down fine for my needs, lithium 18 holer does 27 holes easily so I can do 9 on a Wednesday and 18 on Saturday between charges. No real downsides, the S1 and FW3S are both decent trolleys, i'd go with whichever you can get cheapest.