I had the Pro Comp 4 inch lift installed on my 87 a few years back. It's OK. I don't really off road much but it's nice to have the clearance when going to Tahoe in the winter, etc.
The issue I had was that they put blocks on the rear OEM springs, which were already low, so they always bump when I hit small bumps in parking lots. If you have an option, get the kit, but get new 4" springs in the rear, and maybe smaller bump stops for more travel back there. getting new 4" springs is one of my long term goals on that truck....