I've tried Lezyne, the handle is quite uncomfortable. It's probably much lighter and slimmer, but as far as the effort (muscles) used to pump, does anyone know which one between Lezyne and Topeak is easier to pump at high pressure?
The laws of physics can't be violated no matter who makes the pump.
Ease of pumping is a function of barrel diameter. The smaller the diameter, the easier it's going to pump.
So why would anybody want a pump with a fat barrel? It's because a fatter barrel lets you move more volume so it takes fewer strokes to reach your desired pressure.