I have the former laptop (macbook pro retina with 16 gb ram), and it is really nice. Things are zippy with the included SSD.

The retina display can be set to give you 2880x1800 resolution; you could put the Bitcoin client and a browser side-by-side with no problems.

Dualboot: You can use OS X's included Bootcamp to switch between Windows and Mac on boot. Windows runs natively.