Greetings,
I potentially like them for the following reasons:
1.the inside of the fitting does not need to be cleaned saving time
2.they cost less than the cost of a fitting plus solder
3.the joint is equally as good
4.both sides can be soldered at once
5.they are easier to use in hard to reach places
I potentially don't like them for the following reasons:
1.the inside of the fitting should be cleaned no matter what they say
2.they cost more than the cost of a fitting plus solder when you don't pay HD/Lowes prices for fittings / solder
3.the joint isn't actually equally as good in practice
I definitely don't like them for the following reasons:
1.the shelf space they occupy displaces parts which I do use and need
2.they interfere slightly with glued pipe insulation
3.both sides can be accidentally soldered at once
4.they are proprietary (I believe) and the price may be increased at any time???
5.they call attention to repairs performed (people don't like seeing patches)
6.they don't have the same variety of parts offered (no reducing T's in sight, etc)
7.I have mad soldering skills under the existing system and I wouldn't want anyone changing my qwerty keyboard layout either
I definitely like them for the following reasons:
1.Homeowners will see that the solder is already in there and declare that now they can do their own plumbing. They will rush home with their sample pack and solder fever determined to go solder something right away!
Hope this helps, William
PS: Home Depot was giving away trial packages of them for free near where I live.