Blogspot vs WordPress vs LiveJournal vs Weebly vs Blog vs Posterous vs Webs

I'm trying different blog platforms simultaneously, to see how they stack up. You can see Ari Schindler on WordPress, Ari Schindler on LiveJournal, Ari Schindler on Weebly, Ari Schindler on Blog, Ari Schindler on Posterous, and Ari Schindler on Webs. Any thoughts on which platform is the best and why? It sure looks like Google moves Blogspot blogs to the top of its search rankings, ahead of more established sites with better organic links, but its hard to confirm without more controlled testing.