we had an 01 with 130,000miles it was great no major problems any jeep before 2005 is a good buy (at least i think)
we have 3 2004's and they are great the only thing you have to check is to dee if the recalls have been fixed
for 99
http://www.internetautoguide.com/auto-recalls/09-int/1999/jeep/grand-cherokee/index.html
for 00
http://www.internetautoguide.com/auto-recalls/09-int/2000/jeep/grand-cherokee/index.html