As a hound and a meat lover, I'm a little embarrassed to say I'd not been to Bartley's Burger cottage before yesterday but the stars aligned and so I was able to check it out. Executive summary: I liked it well enough but it didn't fog my glasses or anything. Sullivan's in Somerville still wins my vote for Best Burger in the Boston area.
I got the Laura Bush (bacon, cheese, lettuce, tomato) and it was perfectly medium rare, as ordered. My friend got the Condaleezza Rice and it was basically the same but with jack cheese and some red onion. We each opted for onion rings over fries. He had a lime rickey (delicious) and I got iced tea, basically instant Lipton, not brewed. I liked the burger and the quality of the meat seems superior to Sullivan's. But only the merest bit, and after the upgrade to o-rings and drinks it ended up being a $15 lunch. The rings were good, but not worth a $1.75 upgrade or the extra calories.
So, for now I think I'll stick with the Sullivan's "price point" when I need a burger fix which is about once a year. On the other hand, with the reopening of Tim's I could do a horizontal (literally!) test while it's fresh on my mind. And Charlie's looks good too. I need to revisit.
And by the way, the bearnaise burger doesn't exist anymore and hasn't for quite some time so the person who recently talked about that option must have been there a while ago.