Purchasing, carrying, and maintaining two devices is expensive, heavy, and tedious. Easy always beats safe. Not to mention that there may be significant overlap between work and play for some people. I code Magento (PHP) during the day and contribute to open source PHP efforts as a hobby. In which environment (work or personal) should my notes and bookmarks be?

When I have a company issued laptop I use two machines. When I don't, then I use two accounts on the same machine. Most Linux distros even allow fast account switching in different virtual consoles. I use a different background and panel color for the personal and work environments. It's not a perfect solution, but neither is separate devices.