There are may different types of limited slip differentials, traction lock, full spool lock ups, etc. There are benefits of course, but only for specific applications. There is an increase in initial cost, there can be an increase in repair, but if taken care of, then? There definitely can be an increase in noise, but in my 8" posi-trac that I have now, there isn't any noticeable noise.
For the type of driving you do, I wouldn't say you need posi-trac. But who knows. You may like it more than what you now have.
I have always loved posi in my 57 Chevy, my Olds 442, my 65 Corvette, and in my Falcon. You can probably find a million other pros and cons on the internet. Larry