Homed at BOS with many a night in the LH lounge waiting on TATL. Don't bother. I don't even go there when i'm flying from E anymore, as the terminal has mediocre WiFi for free and I don't booze before flights. Legal Seafood's the best option in C, but they've added a bunch of new stuff there since the JetBlue buildout and the security renovation. There's also some decent stuff outside security, as well.
The only thing choice in Terminal E is the rotating pop-up restaurant space, where Boston's chefs take turn feeding the masses. Frankly, I'm not even sure they're still doing that.
Timothy