My DS uses Flonase, and when it works well, he sleeps through the night, is rested, and well behaved during the day.
When it's not enough, and his nose is still blocked, his sleep is poor, and he's much more difficult during the day.
He's also on Allegra, and we found through trial and error that Zyrtec makes him absolutely hyperactive and crazy. Different drugs affect different people differently.