I'm extremely happy with the location — it's arguably the most well-positioned area of Brooklyn. Almost everything of interest is 20 minutes or less away: Union Square, Village, SoHo, Midtown, and also transportation hubs like Penn Station and Grand Central. Greenpoint and Long Island City are both a super quick ride, and while south Brooklyn takes longer to get to, I can get to Fort Greene in 17 minutes, and Park Slope in 30. (The most egregious lacuna is to Brooklyn Heights and the surrounding area, but the ferry service is very enjoyable, and the bus is not bad either.)
The main overcrowding occurs during rush hour on the Bedford Ave. and Lorimer St. stops, the former of which is the only stop in a very dense area of recent urban (over)development. Lorimer isn't as bad, and it gets progressively much better the farther out you are.
Of course that was not sustainable long term, but most people didn't think about that, or didn't care.
I work with some of these people, but live in upper Manhattan. I spend a LOT of time commuting to Brooklyn.
Access to an Internet connection to email mom and dad in the Midwest and ask for more money for rent is also a common preoccupation along the L train corridor set.