ComputerAndVideoGames.com has tossed up a review of New Frontiers, giving the free RvR expansion for Dark Age of Camelot an overall score of 80/100. Their final paragraphs:
When you consider all of the new additions - including new RvR 'battlegrounds' for all levels from 1-44 (yes, you can go from whacking kittens and puppies to thumping Vikings and Celts before you're out of nappies), along with the free upgrade of the graphics engine for anyone still using the original Dark Age client - New Frontiers is a steal at, well, zero cost.
For new players, coupled with Mythic's new 'free level a week' program, the new battlegrounds offer some incentive to start anew, but low participation on most servers makes this problematic. If you have existing high-level characters, it's a must-have.