Just a small follow-up:
Recently I'm developing most of my PHP projects both in PhpStorm and PHP Tools in parallel.
(Debugging in PHP Tools is way more easy and way better than in PhpStorm).
Today I had the situation that PHP Tools did detect two errors that PhpStrom did not detect.
So in this context, regarding this quote above of Jakub:
...basically disabling our diagnostics...
I'm strongly recommending that you do not disable your own diagnostics and solely use PHPStan output.
Instead you should keep (and constantly improve) your own diagnostics and add PHPStan output additionally on top.
Otherwise my today's errors would go totally undetected.