As long as you install the SharkBite fittings properly then they are very reliable and you should have no issues with the SharkBite fittings leaking.
I've installed several SharkBIte fittings and never had any of them leak.
Make sure you cut the pipes straight and remove any burrs from the pipes before pushing them into the SharkBite push to connect fittings.
You have to make sure the pipe goes all the way into the SharkBite fitting and make sure it grabs onto the pipe properly and use the correct SharkBite fitting for the type of pipe you are using.
If you use the wrong SharkBite Fitting on the wrong pipe type then it could leak so make sure the SharkBite fitting is compatible with your plumbing.
When installed correctly the SharkBite fittings should last many years.