The B3 release plays very well, it may be thar our regulars have getting used to the map layout, but the gameflow is more fluid and the fights are really intense. You did a good job at fixing the many issues with your four capture points. B and C are now fought over, and if somewhat spammy, this kind of action is not based on pure chokyness. Attackers can get from anywhere, and you never have a easy time when standing on those points.
The layout on D now corretly prevents spawnkill tentation, and if it looks like really hard to take, its definitively possible. The vent passages you've added are not too useful for direct attacks, but gives demomen, snipers and soldier a good opportunity to take out key red players, and leaves a meancing aura that makes life for people coming from the main hallways easier.
On the cons side, the map certainly has that indoors feeling and lacks larger areas, but it gives its flavor to the map and doesn't create situations as extreme as say, junction. Certainly not an "arena feeling" like gravelpit point A, though.
Graphically, you've made some nice blend of rustic and new, and if it's not totally consistent, it leaves a sens of progression along the map. The use of curves, plants and acessories, create a modern lobby atmosphere seldom encountered. The work on displacement and water is nice too at the start. You should only adds some roundness and noisiness in some of your displacements. No perfs issue encountered so far.
A map with both a creative layout and look, keep it up !