Meteoric armor isn't common in my DF game.
It's a niche armor in a world where magic is relentlessly hostile much of the time, but vitally beneficial as much of the time.
But it is useful in certain circumstances. Here is basically what I do in my DF game.
Stops Touch-Based Spells - Meteoric armor stops Melee spells cold. They simply can't work on a bodypart covered with meteoric armor. A fair number of monsters in my games have touch attacks, and some of them are magical. They won't work. Since some of those effects are stunningly lethal, meteoric armor brings you from "dead" to "unharmed" for some mere cost of DR in other circumstances.
In fact, it'll fail to trigger touch-based spells of any kind, so if someone casts by touch to cut the range penalty to -0, too bad, it doesn't work. A step by a meteoric iron boot might be noisy but it won't set of Nightingale or Watchdog or Link. You'd need to be fully encased to totally ignore Regular spells in my game, but you're still doing well if you can ignore some other spells.
Most spells create some kind of real, physical effect, which makes negating those spells tricky. A very strong ruling on meteoric would say that they negate that effect - so a sword created with Create Object can't hurt you, a Created Warrior can't punch you, a Cornucopia created arrow will simply fade away. Would this extend to Missile spells? It could. They create a very real effect, but it's temporary. However, this is a slippery slope down to "immunity to all physical effects from magic" which is more potent than I think it's worth making it. If you can ignore the fire from Create Fire, can you ignore the wind from Windstorm or the temblor from Earthquake? Seems iffy and difficult. You can carve out niches, though - perhaps things based on Create Object simply don't have any effect, while spells that create a real "thing" that lasts on its own do (so Create Fire would work, but not Fireball). Ironically, in this case the best way to attack someone with meteoric armor is to directly attack the wearer, not try to penetrate the armor!
It ignores magical armor penetration spells - If Penetrating Weapon is indeed priced as low as the books say it is, it's going to be common. It won't work on meteoric armor.
You can equally say it is fully proof against magical weapon enhancements of all kinds - no Puissance either - none of the offensive weapon enchantments have any effect on meteoric armor. Simply ignore them - they're the magical effect of enchantments/temporary spells that can't work their magic on the armor they hit.
Proof vs. Magical Sight - Magical detection spells can't trace a line-of-sight through meteoric armor. This seems minor, but it does mean you can hide small allies behind your meteoric shield to avoid Sense Life or put a special item in your pocket and ignore See Secrets.
And by the way, don't forget your meteoric iron shield is a weapon, too. A meteoric weapon at that. So is your meteoric mailed fist . . . Spiked Meteoric Armor is probably a great way to go for grappling magical creatures with touch attacks.
These aren't an overwhelming suite of powers, really, for some pretty pricey armor. To be fair, most armor enhancements are very pricey for what they do (look at fine, at +9 CF!) And again, it's a niche armor type. In my opinion, it makes for a good special armor piece (a breastplate or gloves when you expect to deal with touch-based attackers, say), or as a shield (all the bennies of an iron shield, plus it's a meteoric weapon) than a general-purpose armor set. But the same can be said for others - spiked being another example. It's very useful in a narrow band.
That's basically how I deal with meteoric armor in my game.