Having almost given up on Grav/Storm,

I have to say that Freezing Rain is a heavy dose of pure joy and I'm glad I stuck with this. Everyone on the ice patch is immobilized and falling down, everyone else is held or being thrown around, and I'm just grinning ear to ear.

Nyx made Grav/FF sound rather tempting, and I may still try it later, but having Freezing Rain in every fight, thanks to (sigh) Hasten, even though it makes my hands entirely the wrong color, is more fun than any other single power I have.

Storm gets its worst powers early. Both Gravity and Storm are late-blooming sets, so that makes it hard to get through the low levels. After Freezing Rain, just about all of the Storm powers are good . . . but you have to learn how to use them. Visually, Storm is the best secondary there is -- it just looks cool. Especially Hurricane, Thunderclap and Lightning Storm.

Gale is the one power I wish I could skip. In upper levels, I almost never use it . . . mainly I use it once in a while because I have it, not because I need it. O2 Boost is a weak single-target heal with some other benefits -- a decent power for teaming, but useless solo since Singularity can't be healed. Snow Storm is situationally useful, with a large amount of -Recharge, slow and -Fly. It can help Gravity in those low levels by reducing the amount you can be attacked.

Freezing Rain is awesome . . . not only for the knockdown (with Crushing Field), but also for the huge Resistance and Defense debuffs.

Steamy Mist can be combined with a Stealth IO or Super Speed for full invisibility. I take Super Speed on almost all of my */Stormies (and I have a lot). Plus it adds AoE stealth, Defense and some Resistance to three types of damage. Not bad for one toggle.

Hurricane is not only a positioning tool and a personal protection power, but also has a HUGE ToHit Debuff. But if you run it all the time, you will thoroughly frustrate your teammates. Hurricane is great if used strategically, but can be a problem if misused. It takes practice to learn to "herdicane," which is using Hurricane to push foes into a tighter group while debuffing their ToHit. I love using Super Speed for this.

Thunderclap is skippable on some characters, but great on any character who already has an AoE Stun to stack Stun on bosses or extend it on minions. Gravity has a Stun in Wormhole.

Tornado is another situational power that does a lot of things including a good amount of damage over time. Gravity does not have -knockback in its AoE Immob, which helps Freezing Rain. But other sets can use -Knockback to make Tornado into a pretty good damage power, while with Gravity, it will throw foes all over the place. Still Tornado has its uses . . . an auto-hit damage power works for finishing off those annoying Paragon Protectors who have hit their last second MOG, and it adds a lot of damage to AVs with -knockback of their own. Plus it makes another good "panic button" power. I find that I use Tornado a lot more in the late game than I did leveling up.

Lightning Storm is just nice. A cloud over your head that shoots lightning bolts with good damage and knockback.

A Grav/Storm is significantly made more effective with its last few powers, especially Wormhole, Singluarity and Lightning Storm. The lower levels are tough to get through, but it really gets fun later.