These are some of the best platforms for blogging: WordPress.org, Web.com, HubSpot CMS, Gator Website Builder by HostGator, WordPress.com.
In fact, there are a lot of platforms. When choosing a platform, the user evaluates the cost of the platform and its functionality. And then he chooses the best option.
Should not say best as there is no real way to measure that. Maybe except for WP as it is number 1 CMS there (however VHS became number 1 video format, but was definitely not better than Beta), but this is also very subjective. You can only say it is your favourite platform, or the one that works best for you.
Professional website with your own domain => WordPress.org Super easy blogging without paying a penny => Blogspot.com Another is, that Blogspot won't pop up an ad asking you to upgrade. Happy day!
Wordpress is the best, if you want to do something great, I recommend you to buy a cheap hosting ($1/month) and a domain ($10/year) and install Wordpress.
Wordpress is not the best. The best is always appropriate solution, depending on situation. And cheap is not the best way to go.
I think Blogger is the best blogging platform for your personal blogs, where you can write your thoughts without any charges, even you can run Google Adsense, so you can earn without any investment.