First time I used them was for one way coach and back in first domestically, skip to when I made diamond status my first major trip was flying JFK-CDG-HEL-CDG-BSL-CDG-NRT-CDG-JFK for 220,000 miles in J then 5 months later LGA-DTW-HKG-NRT-JFK for 200,000 miles and my next trip in December JFK-NRT-BKK (own fare to Phuket)BKK-NRT-JFK for 180,000 all in J.
Oh and flew a friend of mine in J JFK-LAX-HNL-ATL-LGA for 100,000 miles in July. I paid for myself and only cost $1,300.00 in J/F (coach was $900.00)