This is a very useful assist because you can use it as a projectile if you wish, due to its fast travel speed. You can also use it to extend combos as it does a good amount of stun and keeps the opponent on the ground.
Dragon Punch (Shoryuken)
This variable counter performs what you would expect it to. It is easy to follow-up.
Hyper Fireball (Shinku Hadouken)
Shinkuu Hadouken actually isn't that great in VHC's because it adds a lot to the damage scaling. It is very useful for Delayed Hyper combos though.