Been playing for 4 months, have 1200ish hours and midway into World 6 while playing at my own pace. Other than the $5 auto-loot purchase which feels mandatory, I haven't bought a single thing. I genuinely think people complaining about the monetization just have bad FOMO. Yes, you can whale to speed everything up, but if you have self-control, the game is still very manageable. If you like having tons of different mechanics to explore that all feed into each other to make your character more powerful, and frequent updates, you'll get a lot of mileage out of it.
My complaints are the performance issues toward endgame, shoddy android port that has bugs with overflowing numbers, several mechanics are unfinished, and my biggest complaint is there really isn't much multiplayer outside of dungeons, guilds, and the odd quest/achievement that requires player interaction, which really sucks and makes it feel like a singleplayer game 95% of the time.
3.75 out of 5 stars.