Blogspot vs Wordpress

I've recently been toying with the idea of switching to Wordpress. I signed up for a free account and was playing about with it. Many people like Wordpress for the professionalism it has, the easy navigation and usage, etc. But it does come with a price. It doesn't come for free if you want to customise your blog a lot. However, even with this setback, many are still willing to pay instead of using a free one like Blogspot.

So what is really so attractive about Wordpress? I'm curious and I want to know it all, pros and cons, before I make a decision whether to stick around or switch. And why am I thinking of switching, you ask...I don't know. Maybe because I just need a change :)