You'll be back, again and again.
People often consider the graphical aspect of games when thinking of playing one. MapleStory has very pleasing 2D graphics. If you have an interest in anime or cute graphics, then MapleStory is for you. The graphics are very aestheitcally pleasing. The 2D gameplay makes MapleStory even more fun to play if you enjoy playing 2D games.
An extremely bad point of MapleStory is the levelling stage. It can be very tough to level in MapleStory if you don't know where everything is. The levels become extremely lengthy and time consuming around the level 30 mark. At one point, you could be level 70 and be spending 8 hours to just level once; this is far too many hours in my opinion, but the fun-gameplay makes up for it.
There is much more content in MapleStory now than there was a few years ago. Each month it improves and adds new content. There are also many versions of it so you can play with people in the same continent as you. With all of the new content, you are able to join others in Party Quests, do quests yourself, train on monsters, explore deeply, buy many items, and make many characters of different classes.
When it boils down to a conclusion, I wouldn't advise playing MapleStory unless you have a lot of free time on your hands. I can't stress the words a lot anymore. You will need hundreds of hours in order to progress through the game at a steady pase. If you do have that, then enjoy your MapleStory experience!