It gets boring over time, even during lvl 10-20. It's fun if you have friends to play with. And in dungeons you'll either meet lv50 players rushing for their lives and leaving the newbies behind or get paired with lower lvl people who keeps on dying.
Challenge: managing resources, pots and dumplings (pots too) are not cheap, they're expensive and you'd rather hunt for them. Learning animations to know when to dodge and surviving tough battles if you're a squishy class like BD.
It's free, so that's one thing, but this runs heavily on your PC/ laptop. If you're planning on downloading the game, play it like a solo game, it's very rare to find people to talk to you. (or that's just me, maybe change servers?)