My main problem with the Magrider:

If you stand still in the Vanguard you're doing something wrong.
Also, within about 200 meters or so, any evading of tank shells the magrider does is thanks to the guy shooting not having mastered aiming. Beyond that distance (or around 300 meters onwards) the Van and Prowler can move fast enough to evade magrider fire, so nobody "wins" there.

It's undisputed because the TR are also notorious for going 1/2, which should skew a numbers, but it only does so for AV. For AI the prowler is still king, even with the high 1/2 usage.

Do you know what a magrider zerg won't have? The space to use their mobility to full effect.

That depends of course on the terrain. On esamir 20 Magriders won't have problem using it. And if it gets to tight, they just use "Spider-Mag" ability to climb hills

Hmm....somehow there exist round about 2 Magrider pilots on Miller of which I´m wary in my Vanguard. If a Magrider engages me and does not have one of those 2 nametags inside I will not even bother to use the terrain for cover or do anything fancy except annihilate it.
Truly excellent players are a serious threat in Magriders, but the average to good players are nothing but free certs for Vanguards atm. The combination of superior armor + shield, paired with the strongest AV weapons available make it easy to overcome even situations in which the Magrider flanked + jumped you.
Also, the SRB? Who still uses that, all of the good Magrider drivers I come accross seem to be using the Halberd which has way better synergy with the hit and run style a Magrider has to employ to stand a chance in combat.
My own Magrider also uses the Halberd as a secondary ever since they turned the SRB into a spasmic lightshow with no punch outside of CQC ( in which the Magrider is easy prey for a VG or Prowler)

Don't want to interrupt but I want to add numbers to this discussion:
(The armor modificator might be outdated, I can't find a better/newer source for some reason
http://planetside.wikia.com/wiki/Vehicle_armor_and_damage_resistance )

Vulcan:
Damage: 167@10 - 125@130
Mag: 60
RoF: 800 RpM (13.33 RpS)
Reload: 2.5s
Armor type mod: 41%
Raw DpS: 2226@10m, 1666@130m (lol, yeah thats gonna happen)
Modified DpS against MBT: 1313@10m , 983@130m
MBT front armor value: 63% reduction
Modified DpS after MBT front armor (Prowler/Magrider): 486@10m , 364@130m
Burst damage on front armor (1,2s = 1 empty Saron mag) = 583@10m , 437@130m

Now for fun: Damage per Minute - including stock reload and mag, since I don't know the exact vlaue of the certifications

Raw: 89011@10m, 66625@130m
Modified: 52516@10m, 39309@130m
After armor: 19431@10m, 14544@130m

Saron:
Damage: 284@ all (Splash is irrelevant)
Mag: 6
RoF: 300 RpM (5 RpS)
Reload: 3s
Armor type mod: -50%
Raw DpS: 1420@ all
Modified DpS against MBT: 2130@ all
MBT front armor value: 63% reduction
Modified DpS after MBT front armor (Prowler/Magrider): 788@ all
Burst damage on front armor (1,2s = 1 empty Saron mag) = 946@ all

Now for fun: Damage per Minute - including stock reload and mag, since I don't know the exact vlaue of the certifications

DpM on front armor:
Raw: 25560@ all
Modified: 38340@ all
After armor: 14185@ all

Sorry for the long post, hope it clarifies things.
Keep in mind though that those raw numbers do NOT account for things like CoF, or situational modifiers, like the Magrider emptying his magazine and then burning past his adversary or one of the tanks taking cover while reloading.

In my opinion the Vulcan is still the worst of the AV secondaries - 30% more potential damage (over an unrealistic time!) against a tank thats close enought to spit on it don't seem enough advantage for the drawbacks of it.

the tr and nc also have the stealth tank option, but for an unknown reason, they don't use them.

Yeah.... lol. You should try spidermaging your way around the problem of being shot at. Not only does it make you move slower, it also hampers your ability to aim.
Even on Esamir you can run out of space for your mags. Not to mention Esamir is the trashiest continent to play on ...

Oh I'm well aware of the harsh drawbacks on the Vulcan, but that wasn't the point I wanted to make.

If they would just let stalker infils hi-jack vehicles.....