Ah man, the first MMO I ever played was RaiderZ back in early 2013. At the time I really enjoyed it, but it soon became clear to me that PWE was a really greedy publisher, and on top of that the developers for RaiderZ (Maiet if I remember correctly) were pretty much done for. The game has since been shut down but for my first taste of MMOs I really enjoyed it.
Then I picked up the Tera Collector's Edition in August 2013, and wow did that game open my eyes. It was worlds ahead of RaiderZ, the classes were better fleshed out, it was actually open world, and it looked beautiful. I met some really awesome people over the 3 or so years that I played Tera, wasted many hours of my free time and spent a fair amount of money on it. Every now and then I patch the game to see what's changed but I don't play it as seriously as I used to back then. I might have a look at it yet again when the next new class comes out next year, it actually looks pretty cool and I normally detest any additional classes they add.
Last year I got really excited about Blade & Soul too, I had been waiting for a western release for YEARS. I played two CBTs last year, then played it on launch until about.. March, I think? I actually really enjoyed that game, and it has my absolute favourite soundtrack ever tbh. I loved the gameplay but I just hated the way NCSoft handled the game. It looked promising at first but they went back on their word so many times, not to mention I had awful ping to their servers in some instances like Mushin's Tower, and they made the upgrade costs ridiculously grindy to the point where it felt like a chore for the couple hours I could manage each night. I don't know if I'll ever go back to the game, it's been months since I've looked at any updates for it but I definitely miss it a lot. Since then I've stopped playing MMOs altogether because of time constraints.
I think at this point the only MMO I'd consider getting into now is Monster Hunter Online if they ever release it in the west. My friends and I have been waiting for another MH to play for a long time since neither of them have a 3DS.