after about 1000 unique or so, blogspot is dangerous place to be. You'll be subject to daily take down attack, disappearing posts, lock out, etc. You won't last posting mp3 in there, even if you are careful. The take down is robotic. so ...
When I first started my blog, I used blogger and it was perfect. While blogger is not as customizable/flexible as Wordpress, it was very easy to use and a great place to start.
With that said, I moved over to Wordpress after about a year on blogger. The main reason was because I wanted to host the site myself, but as the others have already noted, the frequent DMCA notices and lack of flexibility were also factors.
I would definitely go with Wordpress. The learning curve may be a bit higher than blogger, but it's definitely worth it and it's really not that hard to figure out.
I'm one of the few people who still use Blogger after 5+ years. For all the scaremongering - see above - we've had one takedown notice/unauthorised mp3 removal in that time. Which is actually a lot less than many blogs based on Wordpress. Ultimately though, it's pretty much universally accepted that Wordpress has greater capabilities.