Get the trial, thats the best idea. Also ignore all the "Meh, WoW is a grind" sayers, they obviously have no idea what a grind is. Ive played for years, and I can honestly say, if you find you enjoy the game, the maths alone say that its worth the subcription. I will agree with people saying it's better with friends, but that's down to hoe social as a person you are. Yes it is quicker to level with friends, and generally more fun, but there is nothing stopping you from making friends in the game, and with any luck you'll meet some decent people.
Since I've played for a good few years, I've gotten bored of it for the time being, so I'm taking a sabbatical to play EvE online, another game, the as long as you have the patience and willingness to learn, is absolutely brilliant.
TLDR; Get the trial, make up your own mind.