I've been using semiologic for a few years. It's a great WordPress Tool that automatically has some of the best plugins (as well as some custom built) in addition to built in tools to get you noticed by search engines. IT also gives you the ability to customize your wordpress theme with just a few mouse clicks.
The only thing I didn't like about Semiologic was that all my eggs were in the basket of the developer. He is a nice guy, but none the less, if he got hit by a truck, I'd be out of luck for support. Well the interesting news is he has sold the software company to a new person who as he put it, “As a bonus I can readily picture him raining the company's cash onto itself in order to develop it faster — I would probably have kept underfunding it to a point where excessive growth rates are not sustainable.”
So it sounds like more development (included a hosted version) will be coming in the future.
Check it out at www.wordpresstool.com