Just to confirm what others have said, please don't join under the misapprehension that you will get a command after 18 months. There will be some early (3 year) commands this year but then the average time will rapidly rise again.
Can also confirm that 2600 is a fair net figure but this will increase when the current deal kicks in. However IMHO if you want to retire on anything decent, and don't have separate provision, you will need to be kicking most of your pay rise into the salary sacrifice pension scheme.