Trigger doesn't work - HIPERFIRE PDI AR15/10 Drop-In Trigger Assembly

I am normally a huge fan of hiperfire products but this trigger has some serious issues. I installed the trigger following all instructions to the letter and, after running through a functions check was skeptical of the trigger's reset. Far too much travel in trigger and a very clunky reset. When I took it to the range the problems became even more evident, beginning with the trigger actually sticking in the rearward position and having to flick the trigger forward to get a reset for the next round. To make matters worse, the hammer would occasionally stick in a "half-cocked" position and would prevent me from pulling the charging handle to the rear when racking a round. The only fix for this was to open the receiver and push the hammer back down to its fully cocked position. I promptly sent the defective product back and will be going back to hiperfires other products from now on.