Smarty wrote:

I am wondering whether there are any reasons to NOT use Sharkbite
push-fit plumbing fittings other than their relatively high cost?

Rather than sweat soldering, they seem like a really attractive and
very fast way to install copper plumbing without use of a torch or
solder. I am especially curious to know if they are holding up well,
and are as good as they appear on paper.

Any opinions would be most appreciated.

Smarty

The Sharkbite fittings are very much like the push lock air fittings
that have been used for industrial pneumatic stuff for a long time, so I
would expect the reliability is good as long as the O ring material was
properly selected.