I think it is clear that Thor is slightly stronger, this was mentioned in the Korvac saga, where he couldn't quite lift Thor's deadlift.
However in the same arc, he mentioned he was tougher than Thor and his speed and strength combo made Ultron fear he was had the best solo chance against him (bearing in mind Thor actually finished the job).
and its highlighted about as often as Thor gets a speed showing...so I'm not sure of any advantage either way.
As to durability, Thor is overall substantially more durable IMO. That said, Wondy has pretty substantially higher 'hard' durability. As I've described before, its a lot like materials hardness vs. strength. Exceed Wonder Man's hard durability, and he goes down a lot more easily than Thor...in other words, something hard and relatively brittle. Hit Thor at a lower level and he 'dents' or 'deforms' showing damage, but overall can take a lot of damage before reaching breakage.
The old RPG Mutants and Masterminds modeled this with different powers...Invulnerability vs. Toughness. Toughness gave you a bonus to save vs. damage, while invulnerability ignored damage lower than its level, and gave a bonus to save for damage above. In those terms, I'd give Wonder Man something like Invulnerability +10 and Thor Toughness +15