I was torn between Colonies and Atamara but voted Colonies because there is a lot more going on there right now for my two chars there than my two in Atamara (and so that the Colonies has at least one vote!).
I like the sedate, usually polite pace of The Colonies and the mix of people who choose to be there and people who end up there one way or another. Despite the slow pace there always seems to be something bubbling under the surface (and then erupting) and the slower pace seems to give some people more incentive to concentrate on scheming, planning and plotting - for good or for ill while others just to coast along with little pressure to act meaning that motivated characters can change things more so than in more active, intensive and populous continents.
I like that Atamara has a broad range of RP styles from the sublime to the ridiculous and the freedom to create RP storyline that can be full of subtlety, depth and meaning or just plain silly (sometimes with the same character, sometimes even in the same RP!). Where else could a realm's entire council spend a week 'on vacation' deep in enemy territory (culminating in a one-man invasion of their enemy's second city.. which then secedes and surrenders) all the while sending home postcards to their realm-mates about how lovely the weather is and how warm and full of life the natives are.. albeit not for long.