I realize these make the push-in obsolete, but for the price, why would you not use wire nuts?
1. Easy changes. I have a few ceiling boxes that were passing power downstream but lacked fixtures for quite a while. I could easily add them later later without undoing the neutral connections in the box, for example. It was so simple to snap an extra wire into a free port.
2. Easy connections to stranded wire. I can connect to stranded wire device pigtails to a pass-through connection without worrying about the stranded wires getting shredded. I ran many of my ground pigtails to the boxes and devices with stranded to make it easier to fit devices and wires into the box --very little persuasion needed. For light fixtures that use 18 AWG fine-stranded wires (such as surface mounted LEDs), I was able to pop them into lever nuts with assurance that the connection was good and would stay that way under consistent force provided by the spring. They were excellent for making consistent connections to the fine-stranded wires on my Honeywell line-voltage thermostats.
3. Simpler high wire count connections. I have several boxes in my system with four or five hots, neutrals, or grounds connected. For 30 cents I can connect them all in under a minute without needing to twist and cut a bundle of five 12 AWG wires.
If I were doing this for a living, I would buy wire nuts in bulk and install them with a power tool. For occasional use I have no problem with wire nuts. For this project, lever nuts allowed me to get more done in less time and with a lot less pain from repetitive twisting motions. The reduced installation effort was absolutely worth it. I spent far more on cable, boxes, and devices than the lever nuts.
