The 13xx series has gone through a number of changes since first introduced. If I don't consider any nostalgia, or collectable value in the equation I think the latest version is my favorite. The new front pump handle shape is a more comfortable fit for me. I love that they eliminated a lot of the roll pins. The front grip is now held on with 2 Phillips head fasteners, and the trigger frame has a removable side plate with 3 micro torx for easy access to the sear and trigger. The rear grip shape is also better, but no ambidextrous pistol grip will ever feel perfect. The platform was built in a way that really seems to acknowledge people were going upgrade, replace parts, and tinker with the stock model at this point.....and I am.