In terms of hard performance and reliability it's hard to get better than a DeathAdder, the sensor is phenomenally good, the main problems a lot of people have with it (including myself) are the weight and shape. It's just so damned bulky.
I personally go for ambidextrous mice over ergo. With a limitless budget I'd go for a Zowie AM or SteelSeries Sensei.
If I had to pick an ergonomic mouse I'd go either Zowie EC1/EC2 eVo or DeathAdder (despite my hatred for the shape and weight).