Last Aug on a trip to ATH, the only (cheapest) coach fares available were M at 1250 or H at 1400. I took the H and waitlisted for BF. I cleared r/t just before the 24 hour mark on my outbound-- but even if I didn't get those BF seats it was still worth it for me to get the 150% mileage for 150 bucks. So it depends on what available when you purchase. If there were X or L at 450 r/t I wouldn't have paid an addition $900 to waitlist for BF, as it isn't worth it to me, but if the fare is close and no copay is involved, I'll go for it.