That's about the gist of it, FoxURA.
The Dominion's Polaron Beam Weapons is far more advanced than the weapons technology of the Federation - when the USS Odysee comes under attack from the Jem'Hadar 'bugs', the Federation got their first tast of the power of the weapons.
The Beams sliced straight through their Federation shields - the shields were totally ineffective. Over time, the Federation did manage to make a defense against them, but that was only after the Odysee and other ships had been lost.
The Cloning capability of the Dominion means that they can just 'make' a new Vorta/Jem'hadar whenever they need one.
I'm not sure, but I think Weyoun dies twice in the various series (Don't quote me on that though) - the Dominion simply cloned him again.
Dominion space is massive. It is almost equivalent in size to Borg space - that puts it to more space than all of Federation, Klingon, Romulan, and Cardassian space combined!
Because of this, they have practically unlimited resources, are able to constantly churn out starships, and constantly create troops.
In one word, they are invincible. (Which is why the Federation/Klingon/Romulan Alliance won!)
a Jem'Haddar first Omet'iklan killed Weyoun 4 for questioning his loyalty to the Dominion