Greenies work great, but I see more people screw them up than I do who install them correctly.
With 2 #14s, just twisting the greenie on does almost nothing as far as twisting your wires together and leaves a really poor splice.
And for the love of god, leave enough wire so that if the splice has to be remade, you don't need to jam a pair of needle-nose into the box just to hold your conductors together.
