Copper Pipe and quick connectors, Any Good?

[Microman]

Having wifes cousin do some plumbing and electrical in remodeling job on bathroom.

Whole house has copper except where we took out this tub, and now it is gone, and we are putting a pedestal sink where the tub use to be.

The cousin says, that now,, He can try those NEW connectors that you dont have to SOLDER,,

Question: are those reliable, and anyone have any experience with them.?
This area will not be accessible after we get done, and some of it even if we were to crawl under the house, so I dont want it too leak.

Thanks.