They are NOT equally easy to create!
- FREE script - wordpress (I presume you won't waste time with wordpress.com or blogspot.com)
- easy to manage as content is concerned - write a post a day and you're a king.
- you don't rely on a community, even if you don't get comments, you can still do well.
- a PAID script is advisable if you're serious with it. Starts at $140 (XenForo - which is actually my recommendation, since it's an amazing script)
- you need 10-20 posts/day AT LEAST. Usually more. The more the better, so this means a lot of time you need to spend in the forum to create content, reply, manage spam etc.
- you NEED a community. You cannot run a forum by yourself and getting members/posts is not that easy.
So, if you are not too experienced with forum management and would like to start slowly, work on a blog. Grow it, get some decent traffic. You can always add a forum at a later date and funnel the readers to it.