Well, I can share a perspective from the side of someone who uses it, and what I hate seeing on the other side of the table:
First of all, I wouldn't try to null/reserve out-deploy it... you're not going to get anywhere if you try to deploy as little as possible, or hide things, or risk losing because all your units die at the start just to mitigate 2 pods of Grav. The point of that formation is to kill the most it possibly can on the turn it arrives... most of the time, with reckless abandon. What you CAN do however, is use cover, especially intervening models to your advantage. You probably won't see any characters nearby with an auspex (and you can't give them night vision), and if they do commit another pod to accompany this first wave, it's a giant point-sync for getting that auspex in position... A simple intervening line of gribblies + night fighting will easily help you survive all the grav. Put a lot on the table, so that after the carnage ensues you can wipe out all the devastators.
Secondly, Objective Secured units give this formation a really hard time. Once the pods land, the units that come down nearby will probably not make it anywhere else on the board. One jetbike can beat the 900 points of this formation centered around 1 objective... don't forget that. All the models that arrive will either die or remain locked up in combat probably for a large portion of the game (not even hoping to get objectives)... so use your Objective Secured units to make the Skyhammer player choose to target your objective seekers on the drop, or dedicate the entire supporting force of their army to hunting objectives rather than, well, supporting

Finally, ALWAYS voluntarily go to ground if you aren't fearless when the devs shoot at you because giving the assault marines re-rolls is just not worth the chance that they'll fail the charge (unless they're an unrealistically far distance away because of scatter or something). You can choose, when shot at, to go to ground BEFORE you have to make the leadership test. Either way (pass or fail the test) you can't fire overwatch, so might as well take the re-rolls out of the equation; hey, you never know when 2 eviscerators and a vet sgt with power fist might be out there looking to get some AP2 attacks through haha!
Oh and one more thing... lots of Heldrakes... they still make marines cry
