Ready to use vs powder

My baby does awesome with ready to use formula. She hardly ever spits up and loves the taste. We wanted to try powder because it would save us so much money but she literally spits up almost the entire bottle. We burp her the same as we do with ready to use and I even mix it and leave it in the fridge for a few hours before giving it to her to make sure it's completely dissolved. I have also noticed she doesn't like the flavor as much. She doesn't really want to take the bottle with the powder unless she's really hungry. Does anyone else have these problems?