Quoting ARESIV, reply 6Stupid question... is the Maw channeling?
If it would there would be a very slim chance to interrupt it before it eats your fleet.
I just check the buff file and it is not channeling nor interruptable.
Considering that you can actually micro phase jump to the carriers and then consume then, that makes Maw probably the best late game ultimate. All others may have more range or may do more damage to a large group... however you have to be in range first.