I tried it out with a couple of friends before because we wanted to play an MMO together. It was pretty cool at first, but we reached max level really quickly and the game got really boring and repetitive. All the quests are either kill x and/or collect y and/or go to z. It was fun while we were progressing through the story, but at some point we slowly started farming the daily quests using the "go" button (that just makes your character walk to the location automatically and you just had to wait for them to get there) and we all kind of gave up on the game. It was fun while it lasted, but it didn't last long, is what I guess I'm trying to say.
I started off with a human mage, which were apparently overpowered in PvP, but I never got that character high enough to do much with him before starting a new character. I forgot what they're called, but I made a midget race Knight, which eventually became a Blade Dancer, but I kind of stopped playing right after the job advancement because I was literally killing everything and dodging all attacks with abysmal gear. As far as I remember, though, the game was fairly young back then, maybe some stuff has happened in the time between now and then.
Mabinogi is another game I tried, but I only played it for a few minutes before I stopped and never opened it again, so I can't say much about it. I played Dragon Nest for a bit longer (maybe a couple of hours? (´・ω・`)) and if memory serves, it was a pretty fun game, but I hadn't gone through much of the content. I probably would have, if Nexon didn't put dumb region locks on everything and make it a pain for me to play their damn games.