Who is stronger: Thor.
Who is faster: Thor has more speed showings but I don't think there's any real difference in this category. Bill has shown faster than light combat ability recently.
Who is more powerful: Thor.
Who is the better fighter: Thor.
Who is the better teammate Thor has more showings of being a team player when he has to.
Who is more agile: Thor has seemed more agile to me when he has to be. Bill hasn't really shown that much agility. It doesn't necessarily mean he isn't as agile as Thor. He might just not choose to show it.
Who is smarter: Thor has more showings of intelligence. Even genius level intelligence. Although Bill has shown pretty good intelligence in the past.
Who is more durable: Thor. Heat has a more positive effect on Bill.
Who is better without their hammer: Thor.
Who has the better energy absorption: Thor definitely has the superior showings.
It's not really fair to Bill though. Thor has a lot more appearances. Even without them though, the gap between the two has steadily grown to the point Bill was utterly stomped by an opponent Thor at the very least stalemated. There's also the instance right after Blood and Thunder where Thor one shotted Bill. To be fair though Bill was in the air leaping at Thor, but still....
Bill's good, but Thor's just better. For the most part though, they'd most likely be near equals on a typical day to day basis. At least until Thor kicks it up a notch.