I wouldn't let them in the door because I can't bear door-to-door selling or telemarketing.  But years ago my parents bought one - and yep, the salesman stayed for HOURS.  It worked well at first, but in all honesty I think it works much like a regular vac now... and worse still because once mum accidentally vacummed over some dog vomit - and for about 5 years the smell of dog vomit would appear every time she vacummed.  Disgusting.  I haven't heard of that happening with any other vac.  DH bought an industrial wet-dry vac for us... and it soooo does the job, at less than the price of a Kirby and without the pushy sales pitch!