You know, you all seem to be pretty biased in answering the question (except you, Stormcaller).
You don't lose your life to WoW.
That's only if people have such weak willpower that they can't control their playing.
But it's the same for other games, too.
When you start playing a new console game, you tend to play it a lot.
It just so happens that there's a ton more to do in WoW.
As for the $15/month, it's not WoW specific.
Most MMORPG's charge around that much, so it's really not a surprise that Blizz would.
EVE Online, for example, charges just as much.
The high points of WoW:
-If you can find it, there is a fun community.
-There's a lot of content to go through.
-While the PvP may be unbalanced, it can get pretty fast and exciting. That being said, anyone who really knows how the play their class can hold their own in PvP.
-High end PvE content is really neat.
-Around level 60/70, you can see the "old world" content from Vanilla WoW, and there's a lot of lore/background stuff there.
-You feel as though you achieve something when you clear raids/get epics.
-Wide variety of skills.
-If you have friends that play as well, the game becomes a lot more fun.
The ...not so high points of WoW:
-Most of the people in the community aren't very bright.
-The content is very repetitive.
-Levelling to 80 takes a very long time.
-It can get rather frustrating.
-There are a lot of gold dips in the game that can be discouraging (i.e - armour repairs, skill costs)
-If you don't have friends/a guild on your server, it can become very dull.
-A lot of the content won't be accessible until you're the max level.
-When you are the max level, it can get old very fast.
-Flavour of the month classes, and OP classes scour the PvP areas.
Those are just some, but I tried to keep it fair on either side.
EDIT: More people posted while I was typing, many of which are unbiased.