Well I've done it, gone and bought one, been eyeing them up for ages as I need a tent for short stopovers, ebay has an offer on for the tent+footprint so I went for it, got it today and put it up, it does exactly what it says on the tin and goes up in one minute, same with taking down, looking at it I don't think you would get five people comfortably in it but its just me, two little dogs and there will be plenty of room for us, cant wait to use it now :-)
Did laugh at the video I watched where if didn't go back into the bag quite as neatly as it came out, then they cut away quickly in the hope you wouldn't notice.
We have its little brother, the instant tourer 4. It's a cracking tent and really very easy to pitch/take down. Like you say, probably struggle getting five into it but you will be comfortable with yourself and the two wee dogs!
------------- 2015 Trips
January - Red Squirrel
February - Red Squirrel
March - Gimme Shelter
April - Elie
May - Noah's Ark
May - Riverside, Skipton
May - Blair Castle
June - Braithwaite Bridges
July - The Star
July - Witches Craig
July - Scone
August - Highburn House
September - Gimme Shelter