I still think fondly of a 3am greaseburger at Town Topic. Best burger for me lately was mentioned in the article. Michael Corvino has a killer burger at his Corvino Supper Club, and it's available late night.
Based on all the hooplah I tried Westport Flea once. I thought it was overpriced and bland.
LCs ( not the BBQ) in the NoRthland is worth a mention though.
Westport Flea was, for a long time, considered the best burgers in the area. I worked next door to them and knew the owner. He had a handful of businesses in the area. It's been a few decades, but I can't imagine he's still running the show. I'm not even sure if he's still alive. Based on my last visit, I would agree. They are slipping into irrelevance.