I have a classic on 2.04 firmware now. It is a totally different animal to the 1.13 firmware that was there before.
The power I get on screen is maybe 10-20 watts different, higher, to the power meter I have, it has a greater difference the flatter it is, this is similar to before. But the way it handles various situation is way different.
The transitions in gradient are a little smoother and but the momentum side is a lot better for me. I tend to carry a higher speed at the start of climbs for a greater distance than before. I can now climb better as it is saying I am doing 5mph when I am doing 5mph, not the 1.8mph I was getting previously at max resistance. Lastly it is reading a lot closer to actual wheel speed in nearly all situations barring the decents, I have seen some silly speeds in blue there.
I am liking the current firmware and may not update if asked to do so in future for fear of losing what I have gained.