As Hallief3 said, it really is up to you if money is not the issue.
Personally though, if money is not an issue, I would pick to host your own as you have much greater control over it, it will probably be more reliable, there will be no ads on it, you will be able register your own domain and if your blog gets popular you can expand it out into a
website hosting or include a guestbook or forum as well.
Hope that helps you make your choice! I believe that hosting your own has far more benefits than getting it hosted for free
.