Indeed it spontaneously will add markup (mostly paragraphes) and removes some in a obscure way that will mess up your display.
Don't even think about copying and pasting html within this editor which doesn't care weither you made change in the html view or not and rewrite everything its own messy way.
Sadly there are no or very limited control on the rendered HTML.
For instance not being able to customize the send button is a huge issue (you can't even change its value or className).
I had to give up using this extension.
Seams to me you based your review on technical knowledge that you don't really possess ( I'm guessing that MVC doesn't mean anything to you ) and instead of placing some questions on our forum or at least search for solutions on it, you chose to write a bad review here. Thank you very much. :(
Your kind of attitude makes developing and maintaining a free extension something that one would think twice about. Luckily there are a lot of users that are appreciating the time and effort required for such and extension.