Well, first of all, there are lots more differences than just the degrees. The shallower heads are designed to fit on a larger bore engine, and thus, really get big on the valve sizes.
The 23 is the standard heads. Replacements for stock, and some performance stuff. Iron and aluminum. Lots of makers, and lots of various applications. Anywhere from small cc intake runners for lots of torque, to big runners for racing applications.
Then you get into the shallower chamber stuff. There are all out racing heads. Designed for larger bores, like I said. Flow better with the shallower angles, and smaller chamber which does a few things. First of all, it has a quicker flame travel with the shallower chamber. Second, you can make as much or more compression with less dome on the piston. And thus, a lighter piston. Great for big rpms.
When you get to the 12 and close degree stuff, it is one purpose only. Horsepower at huge rpm. There is no use for these heads under about 6500rpm. Some of the heads are dead under 7000+. Lots of sprint car stuff, and other various circle track stuff. As they pretty much stay in the small block stuff with the rules.
Same stuff with the BBC heads. Standards, then the 24's that are stock, just rolled over. Then the 18 degree spread port stuff like Big Chief and DRCE. Designed for racing only. Then the 14.5 sonnys stuff and the 12 degree Brodix and Profiler for bigger inches and higher rpms. Then the 11 degree dart stuff. Just pushing for quicker flame travel, better flow at higher lift, bigger valves, lighter pistons, etc.
This is a very basic answer. If you are looking for a more in depth approach, let us know. But this should help with general understanding.