Definitely recommend P1 polish from Gtechniq! One of my favourite polishes!
The problem with polishing with hand is it take ALOT of time and effort, and more than likely, by the time you are done doing one panel, you will look at the rest of the car and think f@@k that lol!
I guess you have to narrow it down to; how bad are the swirls, have you got the patience to do it all by hand, vs howmuch is someone going to charge to do the whole lot for you...