I don't have the mini, but I've heard great things about it. Speeds are basically the same for the mini as it is for the other, older versions. It's just portable.
Our regular one is rock solid. The speeds I get are amazing compared to the best options available to me. Here's a thread where I posted the speeds I normally get.
https://www.cougarboard.com/board/message.html?id=34904992
Obviously, there are costs associated with having a mobile account vs a set location, so you have to take that into account.