For getting up and running, it saves time. For large projects, it adds leaky abstractions, overhead for each request, a need to upgrade another layer - with poor upgrade compatibility (in our anecdotal case), and very little gain. And it has it's own learning curve, which with modern PHP may be redundant.
Symfony looks better in that it is more of a library and less of a framework, though of course that has its own tradeoffs.
IMO, the weakest part of PHP is the db functions (both PDO and mysqli/postgres)