I find that the rifle simulation systems are quite good and can even give information that is extremely hard to see on a live range. The computer can track every tiny movement of the laser shining through the barrel resulting in a "Mr Squiggle" which gives a massive insight into your breathing, trigger manipulation, position and hold, etc. Expended ammunition stoppages and others can be simulated too, which is very valuable. For rifles and some other weapons (grenade launchers etc.) 20 or so people can be trained in a single room at a time, each with their own lane just like a real physical range. Wooden structures can even be placed in the rooms in order to practise alternate positions useful for urban combat drills.
The tactile experience of holding a weapon that is almost exactly the same as the real thing simply cannot be replaced by headsets, keyboards, mice or non-realistic controllers because if they are not exactly the same there is little or no training value.
Keyboard and Mouse type simulations still have a purpose though as missions can be run in order to create realistic scenarios that leaders can use to practice leadership stuff. I happen to know an ARMA mod is used for this in a particular place.