I think them both... but I can't decide which I like better and if I really like them for sure. It's very confusing... I think I like Phish more sometimes.
I like them both. Everyone says they sound similar but I don't really think they do all that much, except maybe some of the chord structures, but they're two very different bands. The Grateful Dead are more country/folkish and Phish are more Jazzy, but they're both great.