MOOG ball joints aren't any good these days. The factory Spicers last much longer and are far cheaper. Amazon often has the best price.
On my 01 XJ my factory Spicers went 270,000 miles on 235/75R15 with lots of highway miles plus the dirt roads on my property. The MOOG's lasted 27,000 miles ... until I did about 10 miles on Imogene Pass, a rocky Jeep trail. I replaced them with Spicers and they've been fine ever since.
I also run Spicers on my 97 XJ which has a mild lift with 30's and has seen more off roading than the 01 XJ and the Spicers show no signs of premature failure.
The other nice thing about the Spicers is that the press fit isn't grooved so it doesn't eat into the axle C's.