I did dabble with a few PO 2500 in the past and find them quite classic but decided to get a 8500 (black bezel and orange numbers) in the end.
The older caliber 2500 in itself is kinda in between the older 1120 used in older Seamasters and the latest 8500. As such I rather get the latest movement. It's taller if you like tall watches that is. Else it presents a a few important improvements (a very advanced movement, dial and so on) and a few not so important ones (see through case back for example). Bezel is matt and not that shiny compared to the old PO. Don't think anyone outside swatch group is able to service this movement as yet. Not even our preferred watch shop at international plaza.
If you wait a while you might get a much better PO during the Basel 2016. Probably master coaxial and a better ratcheting clasp much like the one on the subc.
Succeeded to become a one watch man...
Rolex Sea Dweller