I used it since August 2014 as a free subscriber, and I really enjoy it.
To add to what people already said, it consumes a lot of bandwidth, even more so if you use video or voice chat. Running both it and Skype/Google Hangouts might cause your computer to overload or one or both programs to malfunction. It happened during a playtest when I had Skype on as well. Then again, at least 2 of my players prefer using text chat so it's not as big of a hurdle it may be for others.