They are close enough bikes. Which one comes in the color or other aesthetics you prefer?
The Scott has a longer wheel base so it might seem more stable and the Tarmac more nimble and agile for maneuvering.
But without actually trying them out, I'd only take that as a guess. Other things might cause that to not be true.
If you are in a hilly area, you won't mind leaving weight behind on longer rides. A five pound difference in bikes for me has made some hills no longer seem like hills. So is one significantly lighter? I doubt there is that much weight difference between the two.
Both new? If not then are the components dated or about to be?