Well, I know that WP.com is based on the MU implementation of WordPress, and I’ve previously had an account at BlogSome, which uses WordPress MU also. I’ve also installed a fair few standalone WordPress systems in my time: Scribble Designs, Unreality TV and others.
Being used to the MU implementation, I was ready for the limitations that come with the territory: there is a restricted sampling of themes available, and you cannot add plugins to your blog. I also can’t currently see any way to add other authors to the blog either, so it’s very much a solitary thing.
Having said that, I’m majorly impressed with the sexy new interface – the WP admin styling has come under criticism recently – and the addition of all-new AJAX features that allow you to rearrange parts of the screen to suit your style of working! You can also expand/contract parts of the interface that you don’t use much in order to conserve screen space.
Another godsend is the ability to add new categories on the fly. This was (and still is) a major downer in the standalone WordPress: You’re in the middle of a post and you realise you need a new category. You’ve got to save the post, go out and create the category, then go back into the post and change the category selection. Not now! You just type in the new category name and hit return. Hey presto! The category joins the list and – wait for it – is already selected, for your convenience!
There’s also a cool new image management feature which I haven’t had the time to play with just yet, though it looks good.
Anyway, that’s all for the moment….