My '88 XJ (with factory heavy duty springs, which is NOT the same as Up Country) has been riding on Monroe Gas Magnums for well over 100,000 miles and I'm still happy with the ride. However, ride quality is subjective, and I prefer a firm ride.
Many of the "name" brand off-road shocks, such as Rancho, will be stiffer than what's ideal for someone who wants the best possible on-road ride. For those people, if they are at stock height I recommend the Monroe Sensatrac shocks. They use a shock tube that has grooves near the center of the piston travel to allow some fluid to bypass the piston, resulting in a smooth ride. As the suspension compresses or droops farther away from center, the grooves end and the ride tightens up.
Because of the groove location, these are only suited for use on stock height suspensions. For an XJ with a budget boost, I'd go with either a Monroe Reflex, or the current equivalent of the shocks I have. That gets confusing, because they don't call it the same thing now, and to further confuse things Advance Auto sells Monroes using a different model name for that particular shock.
