The one thing we've tried with her that we think she may be sensitive to is bananas. They seem to give her a stuffy nose.
Right now, if she sees a person drinking from a glass, she immediately eschews her bottle and demands a glass of her own. But she still doesn't have the concept of sipping from the sippy cup. So we're giving it to her sans valve. It's messier that way, but less so than a regular cup. Now, if only she'll hold it herself!