His lack of telepathy feats post flashpoint worry me, as that would be his best avenue of attack. As far as strength goes he has been impressive, but I don't know if it puts him in Donna's league.
Without his trident and telepathy, I would go with Donna (good flight advantage over him). But his Trident counters magic, Donna's power source, gives him control over nature, allows him to teleport, etc. He is stronger and should be just as durable if not more.
Edit: I was talking about pre flashpoint, I don't know about the new one...
It's more that he has a concentration of strength feats rather than just one every so often. Since the reboot we've seen him lift the cruise ship, lift a collapsed temple off of his back, shift a large land-mass underwater, throw the trident with enough force that it causes a lava flow, towing a fishing trawler through stormy waters, and so on.
A couple more, and he'll be a bonafide CL100.
Just not sure it's enough to beat Donna at this stage, but he's edging closer and closer.