I'm not so techie so I could not easily compare the two. At first I like Blogger because I could easily navigate it. Then, I looked up some "how-to" in the net for my wordpress so I was getting the hang of it. I was building up content for my wordpress blog when I realized I couldn't add any Adsense, Clicksor or Chitika on it.
There's NO PLUG-IN available for WORDRESS.COM
Usually, when I look up "how to add plug in for wordpress" on google, I get a response. But these are for Wordpress.Org usually. You have to pay for it.
I like wordpress better because it's easily seen by search engines and I usually get a lot of hits as soon as I post something interesting. While with blogger, It usually takes 2-3 days more with my blogger.
Here's the post if you have questions about adding Chitika, Adsense to your Wordpress.com site.
LINK TO SUPPORT
In other words, you CANNOT add them. They have an alternative called Adwords. But, to be eligible for this you need to have a custom domain. Thus you have to pay for it. Bummer.