I don't see how a game could really be "that addicting" and I've played quite a few. Well I guess if your life really sucks ass it could be addicting but so could anything else that can take your mind off your sucky life.
As for it being good, it's alright obviously they have about 9 million subscribers. I played for bit when it first came out, it's really made for people who've never tried a mmorpg and like their games on easy mode.
If you want to try a mmorpg that's not easy and makes you think try
http://www.eve-online.com/ (there's a trial).