WoW is the most successful MMORPG, providing hours of fun, until you've figured out how much time you've wasted.
Sure. It's a great game. You'll get in the jive in no time, and start leveling up your character and embarking on thousands of quests.
You have plenty of unique races/classes to choose from, including Humans, Blood Elves, Night Elves, Undead, Orcs, Dwarfs, blah, blah. You can learn quite a few trades in the game as well, in which everyone one provides a good source of income if you do them correctly.
The cost is $14.99 a month. Blizzard's customer service is quite poor, speaking that I signed on a friend and never got reimbursed for it. After countless of emails with Blizzard, all I got were "automated" responses..
You'll quickly start to spend hours and hours in this game. It takes quite a few moons to get your character to level 40, which is your mounting level (where you could get your first mount to ride around on).
Let's get clear that WoW isn't for everyone. This game isn't a game where you could "spend 30 minutes before bed" on. You have to set aside a half day to get anywhere, because of the slow game pace.
WoW to me, even after two level 50 characters, is a pretty damn slow pace game. It just consumes a lot of time getting from place to place. Even the battling is very slow, but it's average for a MMORPG. This won't appeal to everyone, that's for sure.
After months of play, you'll look back on yourself and wonder where it all went. Likely, you might get bored, because the entire gameplay revolves around the same old model- leveling up, getting stronger spells, leveling up, getting stronger spells, leveling up, getting stronger spells, etc.
Not to say it's "just like Diablo", but Diablo is a very fast paced game. I can spend 15-30 minutes in the Diablo series, and get somewhere, and stop playing and live my life. You just cannot expect that with this game.
After awhile, WoW is the same old story. You might get tired of it fast like I did.
I, personally love single player games. Quite a lot of "runs" in this game, you must have a party. And with parties, there are certain rules you must follow to get drops. Don't expect to solo the game, it won't happen. This is a downside I believe, because first, you must wait for a group to form a "run", that could take anywhere from 30 minutes to 2 hours. It's just very time consuming is what I'm getting at.
All in all, it's a great MMORPG. Great, in that it's accessible to most people. It provides the epic story of Warcraft, so there is actual meaning behind it all. But, if your a busy person like me, you'll likely get bored of it after awhile.