In most situations, they're interchangeable. However, there is a slight difference in meaning between "think" and "feel," and sometimes the latter is used to invite more impressionistic and subjective feedback. For example, "What do you think of the painting?" might be interpreted as asking for opinions about the style and content, whereas "How do you feel about the painting?" might be interpreted as asking for one's immediate emotional response.

no, of course they're not the same. 'think' is about opinions 'feel' is about emotions ..so they're used in different situations. (they can be used in the same situations sometimes, but that doesn't mean they are the same!)

They are the same in almost every situation they are used. Brandon correctly explains the nuance.