I would never tell anyone they should go and buy P3D v2! So I leave it up to you to decide for yourself. Some 3rd party devs are charging for their P3D versions, like Captain Sim is, so would need to decide if you buy for FSX, or P3D, or BOTH. I always buy both. :D

But I have no regrets at all about buying P3Dv2.x (Academic Licence).
P3Dv1.x (i used v1.3 and v1.4) was very good, and I enjoyed using it. But P3Dv2.x is way better IMHO. ;D