They weigh around 30 lbs, single line pull is 2500 lbs. I use it mainly for pulling out logs and the tractor if it gets stuck. The beauty is they work when your tractor doesn't and it does not tie up the tractor when logging (I like to use my swinging mini hoe, lifting boom, grapple, or large bucket when logging). I would consider mounting a hydraulic winch to the back of the tractor somehow.
You could make a mount for it and operate it from the operator's seat but you are then getting the negatives mentioned above. Also, the winch is stronger than the tractors holding capability so you are limiting your pulling ability when mounted to the tractor.
Just using rope and directional pulleys is an excellent option for pulling out logs. Use non-stretch rope made for pulling. It works well and is inexpensive. Portable Winch also sells self release directional pulleys which are great if you want to make multiple directional pulls in a single pull (to get around obstructions etc).
Ken