Well, I think it depends... If you intend to put some Adsense ads on your blog and don't want to spend money in buying your own domain you should go to Blogger. If you just want to write in your blog I recommend Wordpress, it's easier.

I used to write on Blogger but now I'm on Wordpress. You find much more plugins and themes for wordpress and for blogger I was not able to find that much stuff to help my blog grow. I also recommend you to buy your own domain, gives you a more professional aspect and attracts visitors better than a free blog.

If you need some more answers on Wordpress and about this subject don't hesitate to contact me, I will help you out.