Yes I have had 3 done. I believe the American College of Gastroenterology? set it as a recommendation for IBD patients, particularly those who have been on prolonged courses of steroids. I believe they say every 5 years is good to check bone health.
Yep standard, quick and easy. One tip though -- they strongly suggest wherever you get the first scan, get all subsequent scans on that exact same machine! So choose a place you know you'll be able to return to!