Ships & Modules

Here's the short and sweet facts:
1. You're only allowed to fit a max of one ASB for ATX. You can fit one of them or none of them. The module isn't banned, just limited.
2. They are very useful when fighting 6-man gangs because they can provide enough boost to tank the enemy for a while (especially on a Cyclone hull) without a Logi and independent of your cap
3. They will be less useful in 12-man fights because tanking 12 people is significantly harder than tanking 6
4. Limiting their use in ATX may or may not indicate that CCP is considering nerfing them. I'm leaning towards guessing they'll leave them alone because limited module matched team fights aren't really that common in Eve, so it's less of a significant issue on TQ proper than it would be in the tourney

Precisely.

Heck, I spent the first half of last weekend wondering why no one was fitting spidertanking Tengus. Then I looked at the rules and saw that non-Logi RRs were forbidden. Sensible for making a good tournament, but nothing like what real TQ combat would be.

Ancillary shield boosters are pretty balanced. It's best to think that they provide a buffer, rather than being an active tank. They do last for a set time.
Get the ehp/s reps of the ship, multiply that by the cycle time of the booster, and multiply that by 13 (Number of charges loaded). This will give you the buffer the boosters supply you, and it's more or less the same if you fit a standard buffer fit.

Advantages:
-You can gain this buffer all over again if you can survive a 60 second reload time
-Smaller signature penalty
-Blue pills and other modifiers can make it damn amazing

Disadvantages:
-Poor alpha survivability
-If you receive more dps than the ehp/s reps, then you'll die before receiving the full buffer
-Fitting ships becomes very creative and difficult. Generally, expect to fit smaller guns and more meta modules.