I have just under 700 hours. My good friend had 1200 hours when he sold his 99 xstar. Another friend also has a 2001 xstar with about 1000 hours. In my opinion, it is a solid and reliable engine.
It is an easy motor to work on. I've found that most parts cross over to a 98 gmc Yukon.
2001 X-Star 5.7l LTR