They work okay, but I don't really like them. When I had to replace my water heater (old one ruptured), I picked up some stuff from HD. The guy gave me SharkBites. I was expecting to solder, but I didn't have a torch at the time, so I figured I would try them out.
Your cuts need to be clean and deburred (they should be anyway) and you need to make sure the connector is fully engaged (pipe inserts by about 1").
The main thing that I don't like about them is they don't do anything to support the pipe or keep it aligned. The connector allows the pipe to swivel and flop around. They are also much more expensive than regular copper connectors.
Also, since they seal with just an o-ring, I'm not sure that I would trust them in a wall. They might be okay if exposed and you can keep an eye on them, but personally, I would like something more solid in a wall.
I have since pulled those SharkBites off and soldered the connections. Although there was nothing really wrong with them, I just didn't care for them.
Soldering if pretty easy. Just get both sides of the joint clean, flux, heat, then add solder. It's even easier when dealing with new pipe that doesn't have traces of water in it. The fitting are pretty cheap, so get a few extras and practice soldering on a couple of them (if you haven't done this before).
If you solder, they also have these heat blankets (run about $15) that are very helpful for protecting wiring, framing, etc. from the torch flame when working in tight places.