Hi,
Yes, don't rely on the performance during editing, and check regularly how it performs when published. That true not just for playmaker but any thing you do with Unity ( and generally speaking for any framework).
Basically, as always, It's a trade and balance between how fast and reliably you can achieve the desire result over how it will performs. If a system allows me great productivity and flexibility at the cost of few frames per secs: Deal as far as I am concerned. Then of course, DO-IT-ALL-IN-PLAYMAKER die hard will require careful profiling. But it's likely that in 99% of cases, playmaker overhead will be completely minimal and likely irrelevant compare to draw calls optimizations, GUI optimizations and physics optimizations.
Bye,
Jean