Since character customization is a huge feature in both games, Big Download started there. CO's character creator has the advantage here, in that it's built on the model that CoH used, and can be seen as a new and improved version. Big Download named it the winner here for its superior, more flexible editor.
However, CoH was viewed as superior for overall customization, thanks to the sheer amount of content. CO will need some time to catch up to that. Champions came out ahead again when Big Download moved on to a combat comparison, for the same reason as before: they took CoH's excellent model, built on it, and improved it.
The advantage moved back to CoH when looking at content, though, which is really the most important point in the end, for most players. CoH is the winner by a mile, because it's got the advantage of time. Paragon Studios has done a great job perfecting what Cryptic started with CoH, and it's had time to add and improve content throughout the game, while Champions is just getting started.
Overall, Big Download viewed City of Heroes as the winner: it's got time and experience on its side. Champions Online is the new kid in school and has a lot of catching up to do, but it's off to a great start and aims to improve with age.