In my opinion blogger can be as powerful as WP if it is used correctly.
Blogger = Clean Unique Content Only.
WP = Whatever type of content you want, I guess.
I have had a blogger blog for 4 years that I update daily. It has over 1200 backlinks that I personal planted myself, no blasts, and the blog is on page 2 on Google for the 2nd most serched keyphrase in the niche. It gets between 900 and 1800 visits per month un-promoted. All visitors are purely organic. I know I could raise the visitors over 5k per month with advertising, or more.
I do not post spun material or copy anyone elses material. It all unique, written by me and is monetized with linkshare and adsense. I also offer a gig that makes me a little money with the blog as well.
Some folks firmly believe in WP, and when it comes to autoblogging, WP is king. But when it comes to natural blogging I think blogger wins hands down when it comes to indexing your posts in google. All my posts are indexed in less then 3 hours once published. Google loves blogger if the content is not copied. I tried to place copied content on this blog a couple of years ago, and out of the 4 I posted only 1 made it to google and it was on the last page of that keyword until I deleted the post.
So, it's a toss up I guess. It really depends on what you plan to do.