The biggest difference is the way in which you control the fwd/backward pulse of the bolt. The led's have your basic 4 dip switches which gives you a limited number of options and the lcds are fully adjustable. The fwd/backward pulse also dictates maximum rate of fire, where you can set your trinity and air consumption.
The actual bolt inside is pretty much the same (the lcds come with quite an air efficient bolt negating the need to upgrade to a red bolt kit) and the gun 20 chip is simply the updated chip that comes with the red bolt kit (more air efficient than the standard led bolt).
As for shot count my LCD with a 1.1 4.5k with just a Pure Rush bolt stop (lets you shoot the tank to pretty much empty) I'm probably getting 1200-1300.(I'm not using the most efficient setting though)
My Led with lcd bolt, Pure Rush bolt stop, Evolve tophat & frontwall/beercan combo, I reckon I'm getting min. 1500 (I don't carry that much paint so it's hard to say for sure).
If your at the next m25 pop over to the diablo tent and you can check em out mate.