Don't have a notion!
I took a look at some of the linked sites from MT.com and all the code behind each one was horrific. Tables, inline CSS/JS, chunks of comments everwhere. The four or five sites I visited were a million miles away from the clean code of WP themes.
When I started using Blogger as a host there was a lot of discussion along the lines of Blogger V Wordpress. So far I've used "free" blog platforms, but wonder about the advantages of paying for extras.
I'm probably confusing a paid website domain with a simple blogging host. I'm tempted to contribute to a domain, but think it would involve a lot of extra work. Since this is a hobby, probably not a good idea.
well I guess when you decide to take it to the next level as a hobby you'll get a domain and hosting ... though having built up your following on the blogger ? site it'd be a bit weird ...
Start as you mean to continue I would suggest ...
40 quid though is 40 quid ... and its a re occuring expense every year ... but its a lot more fun in my opinion to have something you can really mess with ... alter the theme ... have your own me@mydomain email address and so on