They have 50% off at the moment (not uncommon for this time of year BTW). .
I'm "concerned" based on them not having any display models (been to 2 stores) and lack of outside reviews. The tent we are interested does have 1 review on the site which said it was a great tent. A review on another tent said very poor and gave it one star (so Rebel don't appear to be making up reviews). I have a quick look in the bag of the one we like and the quality seems okay.
So, given the sale ends today I need to make a decision and its a $500 decision!
Alternatively friends of ours are upgrading their Kathmandu tentand have offered theres at a good price.