I flew in Phantom mode for the first 2 months until I was confident enough in that "simple" mode.
I then changed to NazaM mode, mainly to enable IOC mode.
I use the P2 mainly for aerial video (non commercial of course) and I love course lock mode for filming....... I usually just fly in a straight line and rotate the P2 on its axis as I pass the subject. Trying to do that in Phantom mode was (at least for me) very difficult.
As mentioned, the light sequences change, so read up on that.
Also I found if you want to change modes in flight, it's better to "stop" / hover..... otherwise if you have any stick applied and changed modes, the phantom suddenly reacts to the same stick input now in a completely new way, which can be a bit unexpected.
Also if you are going to use course lock mode, think about how you want your flying grid to be oriented before you place the phantom on the ground, because after about 30 seconds it locks the forward facing position for use with course lock. I always try to line the Phantom up with other lines, for example the side of a playing field or something.... this helps me remember my grid easily