Make sure you use proper cutters to cut the copper and not a hacksaw otherwise the rough edge could push out / damage the rubber o ring inside the fitting.
No they are not, there are big differences in both design and quality.
Some are "O" ring first grip second (these are more prone to installer error), some have a metal grip ring that can't be re-used and require replacing.
Others are far to easy to demount and can release accidentally (up against a joist or D & D with expansion) or by "inquisitive little fingers)
Some of the cheap systems are, well, cheap.
Some have next to no warranty others up to 50 years insurance backed warranty.
I would suggest a fitting that has the grip first / "O" ring second and that one that can be "locked" or needs a tool to demount it to prevent accidental release.
If you need to find a tradesperson to get your job done, please try our local search below,
or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Please select a service and enter a location to continue...
Are you a trade or supplier? You can create your listing free at DIYnot Local