Definitely very reliable if you buy the legit ones, there’s a bunch of copies using inferior alloys and they will let you down.
Have used them continuously for the last seven years without any problems and have landed carp to 15lb with no problems.
The reason the female adapter might stick in the threaded part of your landing net handle is that the two different metals will react to each other and form an oxide that then binds in the threads. Use a small amount of moly grease or similar and this problem will be avoided.
There were three sizes made at one time with the middle and large one suitable for keepnets and landing nets, the small for pole sock heads and the like.