1. Is functional programming really better than other approaches? (My opinion: Yes, for most applications, although it can sometimes feel more difficult.)
2. Is Haskell really better than other functional programming languages. (My opinion: Haskell has some powerful features that other FP languages lack, but it is often less practical.)
Bottom line: The most important thing is to grok functional programming as a paradigm. There are several good functional programming languages to choose from. Personally, I'm a big fan of F#.