For a western saddle, I prefer wood. The bars need to have some flex, and I'm not convinced the 'flex-tree' saddles flex as reliably as a good wood one will. I once owned a Ralide tree saddle, and won't own one again.
I haven't tried an English saddle with all wood.
I have a Bates saddle with interchangeable gullets. In a perfect world, I think I would prefer all wood. However, if I get a different horse, it would be nice to spring $25 on a new gullet instead of $1000 on a new saddle. I don't know what happened to all the bags of gold in my house, but we seem to be fresh out...
I've only changed the gullet once. My mare seemed to get irritable at times, and she was on the edge between a med-wide and wide, so I took out the wide and put in the med-wide. It seems to have solved the problem, and it only took me 5 minutes.
I don't dislike CAIR, but I have stuffed panels in an Australian saddle, and I think I like it a little better...not much.