I have two SLT-1 triggers and really like them. Like them so much another is on the way...I like them a lot. They were the complete, mil-spec style lowers. The stock mil-spec trigger group isn't great, so I tossed an ALG ACT in one, which is a major improvement.
Precision Arms in Colombia City always seems to keep a couple complete KP15 lowers in stock, and they may be getting some of the version with KE's improved trigger, which I'd like to try on my WWSD inspired build.