I have done both shows...the Power Show and the FS Review. The Review is of course much larger, but is more subject to weather, being outdoors. The Power Show is not really a good place for us, with used tractors, but is a great place to see lots of new and novel equipment.
The reason I don't do the FS Review anymore is 4H. One day, usually the second, of the FS Review is 4H day....kids are given tickets and let out of school, and most wander the grounds unattended. Both times I did this show I spent most of that day asking rude, rowdy, and irresponsibly-behaving teens to leave our equipment alone. I realize the % might be small, but we had dozens each day abusing the controls of the equipment, using a tractor for a picnic table while slopping ice cream, pop, and mustard on it, and congregating while being loud (think portable music player on and a group of teens partying) thus effectively driving off potential customers. I was really surprised, but old-timers told me it's always been an issue.
Louisville is huge, as are a few others across the nation, but the FS Review holds its own. If you go plan to spend an entire day, and even then you will not see everything.