The interface is simple and intuitive. There are only 3 characters classes (fighter, healer, and mystic). PvP combat is rare and must be consensual; both characters have to wear special equipment or go to a special PvP area. Player-created culture is a big part of the game: concerts, an art museum, racial languages, clans and other groups, a university for teaching newer players, etc. This culture has suffered with the population decline, but the supporting game infrastructure is in place. There are world-wide storylines that unfold slowly and whose outcomes depend on how players respond. The player base is more mature than the typical online game, though I know of a few children (e.g., a 10 year-old girl) who play.
The game used to charge a subscription fee, but recently that was eliminated. There is an initial $14.95 fee to start. For a free demo, you can download the client (Windows or Mac) and play an Agratis character, which can explore the world, talk to others, etc., but any experience and coins are not saved when you log off.
My main character is named Torin, so please say hi if you see me in the game. Most people are pretty friendly and will be happy to answer questions, or perhaps even show you around a bit. I plan to make a plug for Cantr on the CL forum, so maybe there can be a little cross-fertilization of the player bases.

A few relevant links:
• Clan Lord - official site, where you can download the game client
• Clan Lord's Unofficial Manual Project - a community-created wiki
• Puddleopedia - an IC encyclopedia, also created and maintained by the player community
• ThoomCare Media Network - news of in-game happenings