It's an okay game, but it's not for everyone.
It's a Korean MMo so there is a lot of grinding to be done. If that's not what you like then you may end up quitting.
Play it like a new game if you haven't played since Pre Big Bang/Early Big Bang. Most of your gear is most likely outdated.

A Reboot server exists if you want to get far into the game with big time investment instead of playing the market. This is the most populated server in GMS. [Disclosure: I do not play reboot]
The tl;dr difference between Reboot and Non-Reboot servers are:
-5x Mesos rate
-Cubing cost mesos instead of NX/Maple Points
-no bonus potentials
-1% damage passive every 2 levels
-higher penalty for fighting enemies above your level(~5% per level vs ~2% per level non-Reboot)
-5x regular mob HP; 2-2.5x experience gain
-no trading with others
-no trading equipment in self storage

If you play outside of Reboot, then you can either play in Bera which is currently the second highest populated server, followed by Scania. Go ahead if you have a group of friends in the other worlds, but you would have to most likely invest in your own gear.

If you live in the EU area, you can also play in Luna for a more stable experience. The NA servers are located in southern part of California, United States.

Will update this if I have to.

It's an okay game, but it's not for everyone. It's a Korean MMo so there is a lot of grinding to be done. If that's not what you like then you may end up quitting. Play it like a new game if you haven't played since Pre Big Bang/Early Big Bang. Most of your gear is most likely outdated. A Reboot server exists if you want to get far into the game with big time investment instead of playing the market. This is the most populated server in GMS. [Disclosure: I do not play reboot] The tl;dr difference between Reboot and Non-Reboot servers are: -5x Mesos rate -Cubing cost mesos instead of NX/Maple Points -no bonus potentials -1% damage passive every 2 levels -higher penalty for fighting enemies above your level(~5% per level vs ~2% per level non-Reboot) -5x regular mob HP; 2-2.5x experience gain -no trading with others -no trading equipment in self storage If you play outside of Reboot, then you can either play in Bera which is currently the second highest populated server, followed by Scania. Go ahead if you have a group of friends in the other worlds, but you would have to most likely invest in your own gear. If you live in the EU area, you can also play in Luna for a more stable experience. The NA servers are located in southern part of California, United States. Will update this if I have to.