Yvonne did a wonderful job for me on an international trip involving a stopover, an open jaw, and two hotel awards. I basically said "Here are my UA, AA, Marriott, and Hilton numbers, here are the dates I want to travel, I want biz class, don't care too much whether it's *A or OW, let me know the options."
She emailed me back about a day later with the whole itinerary.

It was very much worth the $40 or whatever the fee was at the time. (This was when the annual fee was much lower but there was no per-trip option.)
Ordinarily, I'm like some of you in that I like looking for my own awards when they are available online. But I
hate it when I physically have to call airlines on the phone - I mean I dread it worse that just about anything. This one involved some Asian partner airlines - not something that I could just query and book on AA.com or United.com. At least not in 2002.
Only reason I don't join them annually is because I haven't done a complicated multi-country / partner award lately. But if I ever have another one of these trips that requires manual intervention, I won't hesitate to call these guys...errr...girls and have them do the legwork.