Engine mounts/lifts are quick & easy job.
Either way, here are the highlights of motor mount replacement.
1) Loosen the tranny mount bolts at the center of the skid plate. When the job is completed, this will allow it to sit in a "natural" state without putting unnecessary tension on the mounts.
2) Loosen, but do not remove both of the large center bolts that pass through the engine mounts & the brackets on the engine.
3) Remove the bolt & nut (on the stud) that attach the motor mount to the frame.
4) Support the oil pan with a chunk of 2X6 & a floor jack with a small amount of tension, enough to where the mounts just begin to lift off of the frame.
5) Remove the bolts that attach the motor mount brackets to the engine block on just one side only!
Remove that mount & bracket as a unit & change the mount on the workbench & reinstall it as a unit.
6) Tighten the bolts that hold the bracket to the engine to specification.
7) Repeat steps 5 & 6 for the other side. Lower the engine weight back onto the new mounts.
8) Install & tighten the bolt & the nut on the motor mount to frame attachment point. Then tighten the large bolt that runs through the center of the mount.
9) Tighten the 2 tranny mount bolts on the skid plate.
If it took longer than 1-1/2 hours you were screwing off.
Poly mounts last longer.
Poly mounts transmit more engine vibration through the frame.
You decide. We have 2 YJs at our house, both with poly mounts & I never noticed any difference myself.