Here is something really sad:
Dragon Companion:
Dragon Companion - NWN2Wiki, the Neverwinter Nights 2 wiki - Races, classes, skills, and more
vs. the 30th level Dino. (previous link above.)
The Dino is overall stronger.
That's just pitiful.

(..and it doesn't even have the "presence" of a Mega Raptor.)
I tested the Dino with maxed buffs and the epic animal companion feat and the thing was better than many level 30 fighter-type builds with average equipment.
You can even put a persistent "flame weapon" spell on the Dino. (..and vigor, and blindsight for that matter.)
Once fully buffed the thing was doing crazy damage that would "cut" through damage resistance with ease. An *additional* +25 pure physical damage to each attack (a portion of which was Strength and other physical damage from Nature's Avatar and Greater Magic Fang).
The real "kicker" to attack bonuses came from the 9th level spell: Nature's Avatar. **+10** hit and damage. This +10 hit was added to I believe the first attack number of *38*. :speech:
Ok, so where is the let-down?
You can get past most magical issues with Spell Resistance on the Dino. Deathward is also necessary against some opponents.
With the exception of *extremely* high AC opponents, one-on-one combat was the Dino's forte. It excelled at this, rather like a decent Frenzied Berserker build using Power Attack against a single opponent.
The problem though, (unlike the Frenzied Berserker), is that it didn't have any Cleave (or Whirlwind) effect. Multiple melee opponents (or "mobs") took a while to cut-through. This could leave the Dino exposed to the occasion critical hit (..though note however that they were exceedingly rare overall).
IMO this makes the full Druid + Dino the only *viable* true summoner in the game. Gotta have that Natures Avatar though.
(..and yes, fully buffed it took down a demilich in less than 30 seconds.)