I use Tumblr quite a lot, but mainly for work related stuff. There are a bunch of other blogging platforms out there, but I really like how easy it is to edit or create your own theme from scratch on Tumblr via the html/css editor.
There's also something kinda cool about the "style" of Tumblr. For example, things like the GIF search engine they launched recently at https://www.tumblr.com/tv
As a blogging platform, it just feels a little more contemporary than alternatives like Wordpress or Blogger.