How do Alpha Aniimo compare to normal ones?

The size gap is not always dramatic: some Alphas are only slightly bigger than the normal form. Don't expect every Alpha to tower over its species. Bigger is the rule, but the margin varies.

The size is the Alpha mutation itself, and it stays with the creature. A wild Alpha looks bigger than others of its species, and it still looks bigger once you have caught it and untwined it. That makes size the quickest way to spot one in the field, and the quickest way to confirm what you are holding later.

Stronger cuts both ways. An Alpha is the better Aniimo to own, and it is also the harder fight to win before you get to keep it.

Are Alpha Aniimo better to catch?

They are tougher than regular wild creatures, and the catch is not guaranteed. You find one in the wild, beat it, then try to catch it, and the catch only works by chance. Plan for more than one attempt.

You don't have to hunt bosses to get one, either. Alphas roam the world map and turn up in every region as regular wild encounters. They are not limited to world boss fights, so you can come across one while exploring. The named Alpha bosses still exist on top of that, and some of them have their own mechanics. Alpha Baldus, for one, has a chain that links two Pathfinders together.

Not settled: The game tells you Alphas are stronger but gives no figure for how much stronger, and the size difference varies between Alphas. A side by side stat comparison with the normal form is not settled.