I am an authorized dealer for Giessele automatics. They carry a superb line of AR-15 enthusiast, combat, and competition triggers. Price ranges from $180 for the SSA up to $280 for triggers like the fully adjustable High Speed Match w/ 4.4ms lock time. I recently installed a couple of their SD-3G ($245) triggers in a couple custom built rifles and the owners are thrilled. Here's a video of what the SD-3G is capable of (this is not me or a customer, I will eventually post videos of Giessele mag dumps).