Elder Giant Magic - Why haven't I heard of this?

[SorO_Lost]

Also, Reserves of Strength is second party while Elder Giant Magic is first, which may have an impact on it's inclusion in games.

No it isn't.

The Dragonlance expansions were printed by Sovereign Press.
The first book, the Dragonlance Campaign Setting book it's self, is WotC.

Not only is Reserves of Strength completely legit in a campaign that allows mixed sources, but so is Dragonspawn.

I stole some kid's candy last night, it was awesome.

The sad thing is I believe you...

still better than if he stole some kid and left its candy.

Kids are noisy, icky, and smell funny. Why wouldn't I take the candy instead?

[Noliar]

Meh, Reserves of Strength let's you Stun your self for +3 to CL at ECL 1. Technically this is cast NOW, pay later which is more advantageous than EGM. Plus you can mitigate Stun whereas you're always stuck paying the round cost for EGM. Well, that and RoS works with any spell regardless of casting time and breaks CL caps...

By level 6 when EGM finally comes online the only useful trait is that fact it stacks with a better, superior, Feat.

However, with both you can really even more break polymorph, so that's something at least. It's not a bad feat per say, but it is indeed inferior to Reserves of Strength. Also, Reserves of Strength is second party while Elder Giant Magic is first, which may have an impact on it's inclusion in games.

Breaking polymorph with CL boosts is problematic because it still has a cap of the subject's HD and of 15HD. If you have a buffer wizard as a cohort and a crap leadership score then it would be worth the cohort applying these feats to polymorph.

It's more worthwhile with shapechange which doesn't have a cap of the subject's HD. OTOH by that level you probably have better ways to boost CL.