Most of them pay very well. The County Police is an excellent agency with a very good contract, and a lot of specialized units. Yonkers is a good department to work for, too, though there's some political stuff going on right now. I've heard that White Plains guys work a lot of traffic posts, but I've never heard any of them ***** too loud.
Mt. Vernon is the one that really isn't anyone's first choice, due to a combination of factors: lower pay than the surrounding agencies, a generally held belief in historically lower hiring standards (you couldn't make a case for that from the Mt. Vernon guys I've worked with, who are outstanding), and the fact that the city is a ****hole. There's a fair amount of political nonsense flying around, too. They just got a new commissioner, so we'll see what he does.
Westchester county PDs are generally extremely selective, and many of the smaller towns and villages don't hire very often. most of these agencies don't have a high degree of turnover.
The nice thing is that most of the towns and villages hire off the same list, which is established by one test. Some of the larger departments have to be applied to individually, however.
"There is only one basic human right: the right to do as you damn well please. And with it comes the only basic human duty: the duty to take the consequences."
-P. J. O'Rourke