I have been playing Materia Magica on and off for a few of years now. I think the thing that I like the most about it is the fact that it is constantly being improved. It is not just new areas, it is also improvements to the current areas and new features.
It has a lot of mini quests that send you off on journeys to varying parts of the realm and with numerous automated quests that teach you about the game and its areas.
I have never had a problem with any of the immortals. While I realize that most are busy, generally if you are polite and send them a tell, they will deal with whatever issue you have.
There are player run enterprises that give you access to any of the major continents, and can take you through the maelstrom to a different plane called the underground. This can be a fun way to travel around the world. They usually yell in cities saying they are available.
It is not easy, practices are hard to come by and skills and spells do not rise quickly. You can however fully develop a character that suits your personality by picking and choosing the specific skills you wants to use.
It is not a roleplaying enforced game, it allows people from all types to play but interesting things happen constantly! You can always find people that you share interest with and join a clan with similar outlooks to your own.
Because of its large player base, there is always something happening. There is usually an immortal or guide around that can help you if you get stuck. So even if you are a totally new player to this style (like I was), you can get help!
The rules are quite strict. They monitor public channels and prevent people from talking about real world topics on them but there is these chat rooms that can be used to relay from, even when you are in the game world! So you can get a group of friends together and all talk to each other while you play.
For free entertainment that you can play anytime of the day or night, I love it.