You asked if being NYPD gives you and edge in being hired by the NYSP or SCPD, etc... The correct answer is: NO!!
Both agencies are civil service agencies, meaning there are set rules who gets hired and who does not. It starts when you take the written test. They process from the top scorer downwards. If you pass each phase, you move onto the next. If you complete them all, you get hired. Getting hired has nothing to do with what you did.
As a LEo taking the tests, you are actually at a adisadvantage because the correct answer is based on a situation and your response with NO police experience yet once trained, it is hard to thin klike a civilian. Thus there has been some issues in NY where cops on the job are failing entry level tests.
Now once hired, will that previous experience help you? Yes and no. In the academy you will have to learn to do it "their way" which may conflict with what you know. That is where many get in trouble becuase they think the old way they were taught is the best way and do not want to conform. However, the laws do not change and that is a huge relief for you as you will not have to relearn them. Same with some fireamrs stuff, DT, patrol tactics, etc.... And once in the field, off course your prior LEO experience will help.
But as far as getting a job with the NYSP or SCPD or NCPD, it is worthless and will not do anything for. Civil service jobs don't care what you did before, it is all about how you socred on the exam and passd the structured hiring process.
-In God we trust. All others, put your hands on the car and don't move.