I haven't, but I did read up on them as much as possible. For the money, I chose a Rock River 2 stage. I really like it, and it ran quite a bit less than the Ruger trigger. From what I had read, the Ruger trigger wasn't that great of an improvement, and that money was better spent elsewhere. I have no regrets.
I don't know anyone who has tried one. I would be interested to see if they are better than what my impressions were.
I have two of them. They are what Ruger says they are. They break cleanly at close to 4.5 pounds with no creep, or gritty feel on take up. For an AR based rifle it is quite a good value for the $140 street price. It is packed with the trigger exposed, in a handled fixture. So, you can try it before you buy it if you are at a shop that has one in stock. And, if you order one, you can test it and return it with the original packaging undisturbed, should you not like it.
One breaks at an average of 4-lbs, 6-ounces, with a 0.23-ounce standard deviation over twenty pulls.
The other at an average of 4-lbs, 7.2-ounces, with a 0.31-ounce standard deviation over twenty pulls.
For comparison, the Timney in my Mdl 77, set for 2.5-lbs, breaks at 2-lbs, 7.2-oz, with a standard deviation of 0.27 oz, over twenty pulls.