Worth your time if you have the time to spend.
There are many aspects of the game that make it worth while playing, yet its something you have to spend time to get used to. Mabinogi by no means is an easy game to start, and if your not one to be patient as well as want to be super powerful asap then you have another thing coming to you because this game is not all about combat. Your skills are broken up into three segments: Life, combat, and magic. Your life skills are your everyday survival and entertainment skills such as building a campfire, tailoring clothes, weaving threads, cooking, music playing etc. Your combat skills are just as said they are used for fighting you'll learn the battle system quickly, yet it does take time to get used to it, its not just spamming skills. Magic is obviously magic nothing more to be said.
Your skills also have rankings from Novice it increases to F then after intensive training increases to 1, thus by no means is that easy to achieve. Just as in real life without time, dedication and persistence one is not able to achieve proficiency in a skill, and Mabinogi expresses that aspect effectively.
Of course with that being said there is a lot of fun to the game especially once you join a guild, lots of dungeon runs that remind me a lot of the .hack// series of dungeons, but instead of keywords you drop objects to create the dungeon map.
As in all mmo's there is a lot of grinding it might not be leveling by combat per say but it might be picking potatoes or repetitive playing of your instrument to increase your playing skills. It does help, but there is no other word than to call it grinding.
The game is highly customizable from your characters looks to what you want your character to do consider it a life in which you can control and ultimately know the path you want to take skill wise the choice is up to you. True you can obtain all of them, but to achieve maximum rank in all of them takes the patience and extreme mentality of a saint since there are many many skills. Skills require AP and AP is acquired only threw leveling and aging as well as certain quests all in all it does take a while especially as the skills begin to reach higher levels they require lots more AP (many beginning players get frustrated with this) .
Overall if you do have the time to spend on this it is worth while it wont be easy but once you get the hang of it the game becomes attached. The gold spammers that are in the game are only in the beginner city of Tir Chornell in the main square other cities don't have them (in my personal opinion I don't see why people complain just don't chat in the main square of that city you only have to go there to go into the stores).