Is this a good party?

I always have a tendency to aim for my favourite party, which looks like this:

3 Ninjas
2 Summoners

I love this party.
The Ninjas rip anything to shreds with their double attacks, while the summoners toast everything with Bahamut and whatnot, and also act as healers (Moogle) when needed.
I dunno how relatively good this party is, though; what do you think of it?

Pretty good party, I imagine. Especially if some of the ninjas have Steal as a second skill and the summoners have Math Skill. Oh yeaaah.

Any party can be "good"; it's a matter of how the units are used. Innate Two Swords and a decent speed stat basically murders most mage units, cripples fighters, and can at least halve the life of 999 HP monsters (max-level Tiamat?). Summoners need to charge magic, which is why I don't use them; use Math Skill for quick-an'-free magic beatdowns, if you like magic that much. Short Charge helps you along as well.