Your question is really a cheap question to ask cause it has no info about yourself like your likes/dislikes.
If you loved WoW, you probably will not like this.
Aside from that, the good points is that most monster sprites are different from each other. I got sick of most 3-D mmos since most monsters were just resized and recolored. Bgms are not that bad. It has a lot of classes, with lots of skills. There are many equipments that you will strive to obtain along with cards you want to obtain (you can put cards in some armor to give you a boost in power).
Perhaps a point that can really appealing is that you can dual client (or more if you can handle it), when playing, meaning you can play as two characters at the same time (use alt + tab to switch between screens). Often times, one of the characters is a priest made for support.
Now the bad points:
- bots, more than half the population on iro are bots, some may steal your loot, steal your monsters, or just be a pain in the rear cause there are too many on the map to hunt effectively.
- money, there will many things that you want, and you wont have the zenny to buy it cause money isn't the easiest thing to get.
- leveling, its easy at the beginning, but dont forget, the max is 99, and once you reach 50, it might seem annoying. When you reach 70, its a lot harder. Once you reach 86, you might feel like quiting. When you reach 90+ you want to quit. Generally thats how the pattern goes for most people I believe. Good news is that most want to continue playing due to trans, bad news is that you start back at level 1 novice..... (many find it refreshing since it gives them a break fromt the second class and you get to be a over powered player due to extra stat points, and gears you did not have when you first started playing XD).
- Gravity, lets face it, they stink at making people happy. Half the problem is us being jerks, and the other half is them making decisions that will piss off jerks. We don't like bots and want to help get rid of them from the server, but Gravity wont/cant do anything (I'm not sure which it is really). You may eventually buy kafra points (with real money), and gravity will hold special events that may want you to spend more money than you really want to, (in reality, its a marketing tatic, to us jerks, its their evil plot to make more money and it pisses us off). Just in general, most people wont talk of gravity in a positive light.
To be honest, most of the negatives about this game you wont realize until later when you know the game, at that point you can decide to stay or leave. Just give it a try.
If you need any help, my IGNs are: Julley, Leylia, Shiyla, Lynalynn, or HioSatillo