What are the best Planar Bindings?

[robberbaron]

What about elementals with advanced HD? The standard large elemental is 8HD, would it be OK to summon one that was advanced to 12HD?

Same thing, I guess. You get standard ones until you successfully research non-standard ones.

What am I letting myself in for?

 

[Brother MacLaren]

Same thing, I guess. You get standard ones until you successfully research non-standard ones.

What am I letting myself in for?

8-HD Large elemental going to 12-HD? 2 extra feats, 50% more hp, additional +3 attack bonus, +2 to all saves, and 1 ability point (which may or may not affect anything).

A 12-HD Large Elemental is tough, but nowhere near as tough as these 12-HD outsiders: Bebelith (only 13 Cha), Half-Fiend Hill Giant (9 Cha), or Glabrezu (a little tougher to control at 20 Cha).

Templates risk some abuse since they add power without adding HD, but a half-fiend hill giant isn't all that strange or inconceivable.