Lucent Hearts is pretty much your generic Anime MMORPG. If I recall correctly it has a strong focus on couple play. So it has features like marriage and benefits to play with your partner (hope I don't mix it up now). Other than that it is really standard. Normal gameplay with tab-target and hotkeys for skills and so on. With leveling up and so on.
Mabinogi is a completely different story. Mabinogi is one of the most unique MMORPGs there are. It focuses on having an adventure or just having fun doing random stuff. You don't even have to fight monsters in it, you might as well just become a musician and play in town for the other players. There are many non-combat possibilities in the game. Combat itself is also very unique, it's hard to describe so better just watch a video of it. Also in Mabinogi you don't even level up by killing monsters / doing stuff. You level up by real time. Your character will age 1 year every real time week and consequently get stronger until he dies of old age (you can rebirth and start young again).