I have never owned a Dyson before, but I had heard good things about them. My wife wanted a cordless vacuum for quick clean ups downstairs and I try to make a habit of not buying junk. I did some research and was most impressed by the Dyson V8's 40 minute runtime. Couple that with Dyson's reputation of high tech, forward thinking and I was sure that paying three times more than most other cordless vacuums was a solid idea. Once I received the vacuum and read through the manual I felt taken advantage of. Dyson set their own bar so high in their own description that I had no choice other than do be sorely disappointed in the V8. Here are my four concerns:1). This is by far my biggest complaint. The other three complaints are minor, but this one isn't. The only battery spec you will ever see advertised as of 8/30/16 is "up to 40 minutes". In fact, the box says "40 minute" with a picture of a battery. The box has no asterisk, and no explanation. Once you open the box and read the material, you will find that this vacuum only has 25 minutes of battery when used on low suction with the motorized carpet head, and only 7 minutes on night suction. I have no issue with the 7 minutes on high, my issue is with the 25 minutes on low suction with the carpet tool installed. I feel like that should be explained everywhere they advertise "40 minutes". Honestly, I feel like they're deceptive; and I thought Dyson, as a company, was above that.2). Dyson consistently advertises their products as "carbon free" which means they are carbon brush free, known as brushless. They even included a small white booklet (see picture) with this very vacuum basically saying that the electric motor hasn't changed in 100 years, but Dyson is so freaking awesome that they use brushless motors. Well, on page 12 of the user manual, under "operation" it says "this machine has carbon fiber brushes." (See picture) So basically I'm still not clear if this motor is an awesome Dyson technologically superior advanced "brushless" motor, or the old brushed version that they say hasn't changed in 100 years. Why is this relevant? Brushless motors are stronger and use less battery. Also, brushes are a consumable item, meaning they wear out and need replacement.3). Dyson has always advertised that their vacuums never lose suction. The owners manual extensively covers how to unclog several areas of the vacuum.(see picture) The fine print of the warranty says that clogs are not covered by warranty. (See picture). So if my vacuum is clogged, does it lose suction? Of course it does.4). There are two filters that need to be washed in water and air dried for 24 hours at least once a month. I have never had to wash filters on my vacuum before. Maybe I'm just getting old and behind the times on this one, and if so, you can just disregard this criticism. Just be aware, you'll need to "wash" you vacuum monthly.Basically, I'm mostly disappointed with Dyson's marketing and advertising tactics. I feel lied to, I feel cheated. If you understand that this vacuum has a 25 minute runtime when used with the carpet brush or hard floor brush, then it's really hard to justify paying $599. Shortly, the Dyson rep will chime in and explain that you indeed can achieve 40 minute run time using the crevice tool or duster. That's great, maybe you should explain that when you advertise your specs. I, like most people, planned on using the hard floor and carpet brush heads exclusively, so I will exclusively get 25 minutes, never 40. For that reason alone, this is going back.