When we went in May, they were only showing Spectro once. My kids did not see it in prior trips (they were too little to stay awake) and wanted to see it this year.
For the 8:30 parade, I made sure we got back to MK at 5:30 p.m. (my in-laws though I was nuts). My MIL and I parked ourselves on the curb on main street while my DH and FIL took the kids to Fantasyland. Fiffteen minutes later, there were no more front row spots on the curb!!! The time went very fast, we took turns shopping.
I have to say, it was totalling worth sitting on the curb for three hours to have those seats. I will never forget the look on my childrens' faces as the parade went by and the characters high-fiving them. Would I do it every trip, no--but for a three and four year old, the timing was perfect.
What it all comes out to is it depends how important it is to you.