We have two Dysons:
A DC15 (upright, mains powered), that I've hated from the day we got it. It is large, clunky, over engineered and underpowered. It doesn't have the suction of other mains powered vacs, including bag models like the Nilfisk King we had before. Unfortunately, after 12 years it is still going (with a couple of DIY repairs and complete disassemblies). That would be considered a plus, but it keeps me from getting the Miele I want
Then we have a V6 Animal. That thing is the biggest waste of money ever. The battery life is pathetic and so is the battery lifespan. Our second battery is just on its way out. The biggest issue is that it has barely any suction at all. It can't pick up dry cat food (my cat is a pig), it just pushes it around. It's useless for cleaning dust out of old computers and electronics. They are also not reliable either. Ours is frankensteined together with parts from our friends' (who convinced us to buy the V6 in the first place, and whose vac's motor burned out shortly after they replaced the battery). If I ever get suckered into a battery vac again it will not be a Dyson but an LG or something like that.
Sorry to go contrary to the mainstream opinion, but that's my experience.