I had to vote Komatsu for their overall package, but I would have to put Cat and Leibherr running a close neck and neck second. Cat because they are catching up to Komatsu in the breakout power and cab ergonomics and Leibherr for their smooth running hydraulics.
I've had too many problems with Deere/Hitachi products to put them in the running (metal imperfections in booms causing breakage at the knuckle, various hydraulic problems).
Believe it or not Hyundai makes a fairly decent excavator that holds up to hydraulic hammer use, but the cab is designed not for someone of my build. I have to sit with my knees tilted together.:)
I've only used Volvo offroad dumps and wheel loaders, but I like 'em. I also like my wife's Volvo C70 Turbo Convertible but she won't let me drive it.:(