If I replace it, it's likely going to be the EverStart or another Delco.
I wish I could find a Varta. The '04 Jag is still on the same Varta it was delivered with, and still tests as new, for what that's worth.
I think Varta is also JCI now, though, so they may live on in name only.
I wouldn't be that concerned with cca. Thicker/heavier plates don't allow for as fast reactions at the surface, which is why the rating is lower, but they can be more robust too.
Although the original OEM AC/Delco continued to test good, and performed without further incident for the last week, I replaced it on Sunday with a new Wal Mart Maxx battery.
The clincher was finding more corrosion product under the negative battery terminal, even though it had been cleaned a few days previous. It appears to be venting around the negative post.
At full SOC, the Maxx tested at 12.81 volts under standby load in the car, and had 3.63 megohm internal impedance. CCA tested at 785, on a rating of 650 CCA.
The old OEM Delco went out at 12.75 terminal voltage, 6.44 megohm impedance, and 434 CCA on a rating of 650 CCA.