Interesting. I've been making this comparison for a few years. One of the biggest, to me, is where each band got started. San Francisco was the heart of the psychedelic movement and the hippie counter culture, Seattle was the heart of grunge and the musical shift of the 90s. Yes Pearl Jam has (had) more hits, but they're essentially a road band now. The albums (since Yield, arguably) don't mean much but some new life in the setlists. I'd say the fanbase is pretty close to as dedicated, but without the touring lifestyle associate with the Dead. PJ is as close as it gets, I think, in terms of being on a similar level of mass cultural importance (Phish is still too off-the-radar for that)