I'm actually amazed at how different they feel. Personally in PvP my play style suits striker and if there is a defender in the team I will always change to striker. But in PvE defender is far more valuable, especially against bosses where the Hulk smash generally results in death

I saw some Bungie guys talking up the fact that they didn't want characters to descend into the usual DPS, Tank, Healer type roles of other MMO's. I've started changing my config mid-strike for some instances (love the fact you can do this), and I'm wondering if this is more the way bungie want Destiny to evolve? Once you know you sub-trees and strengths, should be a lot easier to reconfig a team mid-way depending on the challenges ahead. Also means teams aren't restricted to always having a certain number of specific roles in them... be interesting to hear what you find works best for different types of encounter (with Titan's)

I've done the same thing put alot of time into my striker now only working on the defender sub-class I'm starting to like the defender class I think the striker class is good too they both do different things in a team The way I see the classes are Striker is agro the crowd drawer Defender is the shield support class thats what i think personally or like to think lol Hope that's helps a lil