In my opinion yes. Did you read the link? $140 for license that never expires, $40/year for support and updates. A one day sale for $100 will occur soon, and they will give one week notice when that will be. No limit to quantity on that day. Beta will be the first version available. There is no way I could state it better than what is in that link, if you want exact details.
I think $140 is a bit steep, to be quite honest. You can get IPB today for $149 and IPB is obviously leaps and bounds ahead of XF in terms of what it offers.
If I have 100 that I can spare that day, I'll pick up a copy. 140 seems a bit much for a script only a few months old..lol