Full disclosure - I sell Aerus DTD
Having said that, not all DTD sales are made as Tom states - Kirby is famous locally for the 'hard' sell. I won't sell that way and I make a good living, I also have almost never sold anything at MSRP. I work hard in my area to network and build relationships and get more than 80% of my business by referral from happy customers. Hell, I have turned away sales where the current vacuum is just fine with some TLC and the $$ just don't make sense for the customer to buy new. However, eventually they do, and they call me when it's time. A potential customer needs to see value in the purchase, I do that by demo but not with pressure. When going DTD I provide information and an offer - either a room shampoo, an air quality check, or even just a request for a written opinion. If and only if the customer initiates a sales/pricing discussion do I even go there. I will happily shampoo your carpet and wish you a good evening and leave you a brochure, which I designed and printed myself because I will not intimidate my way to a sale, and my card. 10-15% of those people call me within a few days to a month and become customers.
Now having slapped myself on the back enough, I will also say that, by a wide margin, Kirby is the most frequently traded in vacuum and then Dyson. Most of both brands are no more than a year old. Last week, I took in a brand new, never even been out of the box after the sale Sentria II. The poor guy couldn't even move the box from where it was left by the Kirby guy. Some people are too ashamed to cancel the sale within the allowed window, some never hear or aren't told that they can. In the past 30 days I've driven 3 people down to the Kirby distributor to cancel sales. 2 of those 3 now use Aerus, the 3rd got her Simplicity Symmetry back and decided it wasn't time for a change after all.
I personally love Kirby, but it's not a machine I would or do take out for everyday cleaning. It's just a bit of a beast and I've got a rather small home. Fortunately, I have a few vacuums to choose from and I do use them all, even the Kirby's from time to time, but my Electrolux Silverado and Epic 2500 upright are my daily drivers.