It's rather remarkable indeed. I really like arcane effects in general and this one looks fantastic with the star-particle thingie dominating the whole thing.
I can imagine the impact sound getting a little annoying if featured frequently, however I guess the idea with it is to boost the "rocket" part of the model, and that the primary purpose of the projectile is that it should be used as some kind of special ability effect. However you might wish to consider changing it to make the model more suitable for frequent usage as well. I'm personally in favour of sounds like the healing spray impact sound effect or orb of annihilation impact when dealing with this type of missile models. Maybe this just got into my head though. The overall feeling of this model is indeed very nice.