Fun for a while, but it wears out. Nice PvP concept, interesting character skills and development.
The 3 factions are unique in appearance and the way they do battle and progress. The Chip Wars, to control the Crag Mine and it's resources, take place every 8 hours and are the highlight of the game. Preparing for this is also fun, but can get repetitive. The Grind in RF Online is similar, if not worse, than other games of this type. RF Onine is often compared to Lineage II, but I see only a few small similarities. Character models are alike and the graphics engine, which I believe is some version of the Unreal Engine.
Graphics are good, but the environments are thoughtless and bland. Sound could be a lot better, but the basics are there. There are many items and drops are frequent at lower levels, but become too spare at higher level. Crafters are key (called Specialists in the beginning), and they can make items that are usually very hard to find, sometimes taking hours to farm.
There are very few quests, and they are not particularly fun. They do give good experience and items sometimes. What drives this game is clearly the PvP, centered around the Chip Wars. However, after a while, there doesn't seem like there is enough "pay-off" for victory. It becomes the same old thing.
RF Online was fun, but it needs more content and more to keep players interested. For the hardcore PvP'er, I would recommend trying it out.