No first hand here, but would like to add that the 945 was made in much greater production than the 845, so it might be harder to find the 845, and prices on the 845 tend to be less than the 945--at least that is what I have noticed from online auctions.
I have a 945-1 and have seen 845s. The frame to me looked the same although the inner workings may be slightly different (I know a 945 has basically the same fire control parts/configuration as a 1911 - don't know if an 845 does though). I would suspect that they would feel very similar in the hand. BTW A 945 feels quite different (thinner at the grip and slightly different grip angle) than a 1911
Actual end results are too close to call. I prefer my 845 over my 945 mostly because of the pivot trigger I guess. Both guns are just as accurate, and I am not the greatest 1911 fan so that might be part of it.