The soft Renthals worked great for me. I put them on last spring and will probably put on a new pair later this spring or summer. I use rubbing alcohol to lube them and they slide right on, no tools needed. I just dribble a bit on the existing grips and inside the new ones. It dries quickly and completely. I don't like to use any kind of soap or oil that may leave a residue since I ride in the rain and am no stranger to big puddles or water crossings. I don't want the grips to start slipping when they get wet.
The urge to buy terrorizes.