Just difference in opinion, but I will humor you. As far as custom maps go, Blackmesa is one of the best, but it caters to a different group than myself. Blackmesa functions similarly to 2fort, in the sense that it's either a roll, or the match can drag for an eternity, rarely is it in the middle.
This coupled with fast spawn times draws in the groups commonly found in 2fort style maps who would rather take down the team than take the flag; very often I find myself on a team with little or no cooperation going on, even when one or two players, sometimes myself, try to rally. Even when a team wins, it is usually due to the lone-wolf actions of others coinciding by accident or happenstance.
I'm not a part of that group, I prefer being on teams with heavy cooperation as well as heavy opposing cooperation from my enemy. I also have disagreements with the basic design of the map, this is strictly my opinion, I dislike the donut shape as there truly no actual places to fall back to, no true safeground aside from areas being turtled by your team. Ambushes can come from literally anywhere, and though this can be solved through teamwork in locking down one of the pathways for the whole round, this requires the aforementioned teamwork which is strongly lacking most of the time.
Like I said, I rarely play it. But there's why. Take it with a grain of salt, it's just my opinion.