Take the attacks with a grain of salt, although many of the criticism is true, it is not exclusive to PHP, ex. the unexpected type coercions.
OTOH, most of the performance benchmarks done against PHP (ex. PHP vs Python) usually mean "which language is faster at crunching numbers". I/O operations like reading a file from disk or running a query against a database are an order of magnitude slower than number crunching, so any of the gains you can get by switching languages become effectively negligible, unless you really care about nanoseconds.
Remember to always pick the right tool for the job, you won't use PHP for number crunching the same way you won't pick C++ to build the minimum-viable-product website of a startup.
To be fair, "number crunching" starts to become really important when you need to, oh, work with the large set of data that you pull back from the database.
But in saying that, PHP7 is actually pretty fast. Probably faster than CPython for most of the algorithmic tasks you might run with data from a SQL database, for example.
OTOH, most of the performance benchmarks done against PHP (ex. PHP vs Python) usually mean "which language is faster at crunching numbers". I/O operations like reading a file from disk or running a query against a database are an order of magnitude slower than number crunching, so any of the gains you can get by switching languages become effectively negligible, unless you really care about nanoseconds.
Remember to always pick the right tool for the job, you won't use PHP for number crunching the same way you won't pick C++ to build the minimum-viable-product website of a startup.