DS did the Pirates Cruise in 2004, when he was 7 and we just did the FM Tour in Jan 2006, he was 9. He said he really liked both & couldn't compare the 2 because they are 2 different things. He said he would take another (different) cruise if it was the Albatross or the new one at CBR but probably wouldn't the PC again because he had already done it.
I asked if he'd ever like to do the FM tour again and he said yes, because there would be different people, other families and probably a different CM leading the tour so it would be different and fun.
The one thing to remember about the FM tour is that you are not guaranteed to have the PP, Wendy, Capt Hook storyline--it can be different. During the same week we were there we saw other characters at the end of a tour interacting with the families, so that is not something to count on. We asked the CM-happened to be the same one we had the week before--and he said it changes on any given day.
Anyway, I hope this helps! They are such different activities so it is hard to compare them. The FM tour is fun if the families are all participating and not worrying about how they look or what other people think. Our group was mostly outgoing but had a few pretty reserved people and that made the CMs job a little harder, IMO.
GL whatever you all decide!
