Well, this is only my opinion:
Cat has automatic stabilizer raise which is really nice, better window latch mechanisms so opening and closing the windows is much easier except for the rear window on both machines The rear window on both Deere and Cat are too hard to operate in my opinion. The Pilot Towers move together with one lever on the Cat which is real nice, Deere are seperate . I also liked the fact that the front bucket of the Cat does not have the center hydraulic piston in the middle of your view.
Deere seems to have better visability and more room in the cab and operator comfort is better. Everytime I swung the seat in the Cat to run the backhoe on the Cat the seat or my knee would hit something and I would have to grab the lever and make the seat go back and then swing around to the backhoe posistion and readjust the seat. It does not do this in the Deere.
Deere has an electric switch to go from Excavator mode to Backhoe mode in the cab, Cat has a lever that you have to unbolt to change the pattern outside near the rear wheel.
All in all this is all minor stuff and I am fine running either machine. Both seem to have similar power.