So Blogcatalog released a service similar to MyBlogLog a little while ago, the similarity's are quite obvious, you can add your blogs, you can add friends, you can join neighbourhoods (individual website profiles), you can comment and network, Blogcatalog also has a widget that is very similar to mybloglogs that shows either your recent visitors or neighbourhoods. All of which you can do with Mybloglog.
What are some of the differences?
BCs widget is I feel a little more user friendly than MBLs, I dislike how MBLs thumbnails cant be right clicked or shift clicked to open in a new window, the customization is about the same, also MBL has another widget option for top links.
MBL has a nice stats package that I use from time to time, BC only has very basic stats about the activity on BC.
BC also shows your recent posts in your blog profiles which I think is pretty cool.
What are my experiences of both.
Very similar, I don't really get that much traffic from both, I found that populating and gathering friends on BC was a lot faster than MBL and I feel that both are a great way to find similar blogs to your own. Blogcatalog has been around for awhile, not in it's current form though, it was more of a directory of blogs and has just as many search results as Mybloglog does and I have found that with BC has more results in smaller niche topics, such as a search for "paranormal" on BC brings up 3 times more results than MBL.
The Big Differances.
Browsing communities on BC is much more organized than MBL, ever things categorized on BC instead of that awful alphabetized system MBL has.
The one thing that am really enjoying atm at BC is the discussion feature they have which I don't think MBL has, it's basically a rolling forum which has a few basic categories:
Shameless Blog Promotion
A lot of great blogging discussion going on here, it reminds me a little of Mylot, only for blogger.