The difference between the hydraulic powered bender and the one shown is that the hydraulic one is self contained and doesn't have to resist the input forces used to bend the tubing. The effort put in to pulling the handle, which can be quite extensive, has to be resisted in the pictured model by bolting it firmly to the floor or other immoveable object. Be SURE you have lots of room to pull the handle and bring the handle to a height where you can apply lots of force and yet still work down on the tube when you're checking the degree of bend.
A slight over bend can be removed by placing one end under a handy heavy object and prying upward with the other arm of the bend. Be gentle, the unbending happens fast.
Pete