I haven't used the sharkbite connectors, but just based on how they work and look, it could be hard to get it clean between uses. Of course, it might not be an issue at all. I would say that if you do go this route, document it. you might be a pioneer in using pex and sharkbite.
I use these fitting from time to time ( not on brewing) , but should work good. The cleaning shouldn't be too bad, although they do have some complex parts. I think soaking will be fine though.
Oh I wouldnt disconnect and reconnect them alot though. They will wear slightly and leak. I had a couple after two dis/re connects that started leaking.
They aren't very rigid connections either. I had to use one at work on I sample line that I couldn't shut off. I cut in a sharkbite valve to kill the line but i feltr like i needed to hold the valve with one hand to firm it up before turning it. It seemed really rickety but got the job done.
I also have used sharkbite fittings on pex for a quick disconnect on other things and it started leaking after only a few uses. The little teeth wear grooves in the pex and then the O ring wont seal it anymore. It could last quite a while if you leave it a little long and cut off a half inch every once in a while.