Timezone-wise? Only downsides. Most of our business partners become more difficult to time-coordinate with, since there are fewer business hour overlaps.
Travel to Europe takes a lot longer.
Culturally, the West Coast is far more chill. Business on the East cost is very much still dominated by banking-style office politics: business casual is suits, or at least slacks and button-down shirts, there's a lot of process, everything is serious. West coast is more laid back. I'm speaking in generalities, of course; corporate culture is driven by the corporation, but in general, the West coast has healthier work environments.
There's less cultural interesting stuff on the West coast, but far more natural attractions (parks, activities, skiing, hiking, camping, etc etc). Everything is crammed together on the East coast - from Philadelphia you can visit NYC, Washington DC, Gettysburg, Williamsburg, all within 3 hours or less. You can get to Niagara within 6. From Portland, OR, it takes 4 hrs to get to Seattle, and a full 8-hour day to get anywhere interesting in California.
If you want a more relaxed life with access to vast amounts of incredible nature activities, West coast 100%. If you want to vacation in Europe and visit a huge number of amazing historical sites, East coast.