I have been using them on an R&D basis.
I have been putting them in areas that can easily be inspected in places that I frequent. So far, all the ones I installed have remained pristine.
They are not fool proof. I check every wire and there is a fairly high percentage of times when I have to re-insert one. They look great, don't wiggle, but a tug will pull them out. Sometimes I have to use a pair of needle nose pliers to get the wire in far enough. If either the wire or your hands are slippery it can be tough to push in hard enough for the wire to seat properly.
Once in correctly, they are very hard to pull out. They certainly won't come out by accident.
The plus side is a fairly big one. My collection has connectors with up to eight holes. Great for places where there may be an upgrade. Just plug and play. They also have places to poke probes into for testing. For me, that is a big plus. They are clear and if there is a problem, it can be seen just by visual inspection most of the time. They take up less space. There is no question as to how many conductors will fit, just count the holes. They ARE removable without clipping the conductor.
My question, one that I will never see answered, is how do they perform over time? I know that connections made with wire nuts last more than a life time, but will the same be true with Wago style connectors?
Just for grins someday, I will do some testing and purposely abuse the connectors and compare them to a wire nut. I will post the results here.
I hope they are safe and reliable and come into general use. As a troubleshooter, having access to conductors for testing is great, so is the ability to see through the connector to the wire.
I wonder if there is anyone that has seen a Wago style connector that was properly installed fail?
Why is it that we just assume the wire nut is the perfect connector and if a wire nut connection fails it must have been done incorrectly?
I don't believe the above is true one bit as I have seen many wire nut failures. They don't work forever in every environment no matter how well they were made up.