In general, I really like this map, both how it plays with a full server and the appropriate and un-cluttered detailing, but it needs some major clipping and optimization fixes.
http://dl.dropbox.com/u/27652498/cp_chasm_a802.jpg
When I go around this corner, my FPS drops noticeably, even when running the map myself to take screencaps. I can only guess that it's simply because there are huge sightlines filled with props around the capture point and they're all being rendered at once.
http://dl.dropbox.com/u/27652498/cp_chasm_a801.jpg
This fence clips with the roof near both spawns.
http://dl.dropbox.com/u/27652498/cp_chasm_a803.jpg
I'm sure everyone has pointed this out in game, but it's super-easy to get stuck here.
http://dl.dropbox.com/u/27652498/cp_chasm_a804.jpg
Floating sheet metal
http://dl.dropbox.com/u/27652498/cp_chasm_a805.jpg
http://dl.dropbox.com/u/27652498/cp_chasm_a822.jpg
First, that spotlight is really hot. Second, the second light on that prop on the red side doesn't have appropriate light coming out of it. It looks weird.
http://dl.dropbox.com/u/27652498/cp_chasm_a806.jpg
I don't really get why you can get back here. It's right next to spawn and it's almost too good of an ambush site for a spy, pyro, or really anybody because the enemy will instinctively not look behind such a large prop.
http://dl.dropbox.com/u/27652498/cp_chasm_a807.jpg
I actually don't know if this is something with your map or the sky texture, but there's a weird seam thing and a lighter colored area.
http://dl.dropbox.com/u/27652498/cp_chasm_a808.jpg
This prop looks like shit up close.
http://dl.dropbox.com/u/27652498/cp_chasm_a809.jpg
Not a big deal, but I don't think it's a good idea for players to be able to stand on these things.
http://dl.dropbox.com/u/27652498/cp_chasm_a810.jpg
This is really nitpicky, but that wire looks like it's coming straight out of the conduit.
http://dl.dropbox.com/u/27652498/cp_chasm_a811.jpg
http://dl.dropbox.com/u/27652498/cp_chasm_a812.jpg
http://dl.dropbox.com/u/27652498/cp_chasm_a813.jpg
http://dl.dropbox.com/u/27652498/cp_chasm_a814.jpg
http://dl.dropbox.com/u/27652498/cp_chasm_a815.jpg
http://dl.dropbox.com/u/27652498/cp_chasm_a816.jpg
This happens a lot throughout your map, at least with this specific lighting prop, which you use regularly.
http://dl.dropbox.com/u/27652498/cp_chasm_a817.jpg
I don't really get why that wooden fence is on a roof.
http://dl.dropbox.com/u/27652498/cp_chasm_a818.jpg
This detailing door on Red's side can be stood on, so it needs to either be clipped off or removed.
http://dl.dropbox.com/u/27652498/cp_chasm_a820.jpg
http://dl.dropbox.com/u/27652498/cp_chasm_a819.jpg
Another example of an unclipped prop that you can climb on top of. A lot of your props around those halls near spawn are like this.
http://dl.dropbox.com/u/27652498/cp_chasm_a821.jpg
Why are these boards here?
http://dl.dropbox.com/u/27652498/cp_chasm_a823.jpg
More unclipped props.
http://dl.dropbox.com/u/27652498/cp_chasm_a825.jpg
These arrows are confusing. They supposedly lead the way to the capture point, but I can see it from here and the stairs are faster. I don't think you need them.