I'm somewhat disappointed with the bag-less vacuums. I use one myself and I also exchanged some views with other users and it looks to me that the centrifugal, cyclonic (or whatever word of the day) technology is just not so effective.
The separation of dust is not perfect. It may work very nicely for larger particle but fine dust goes through the unnecessarily-complex inner workings of the vacuum without stopping. The last line of defense is a good, old-fashioned filter, that you need to clean or wash ever so often.
In my past experience, I had to empty the dust reservoir and clean these filters more often than I would have liked to. I'm using a Bosch vacuum, but my work colleague have the same issues on his Dyson DC19.
My unit also accepts bags (instead of the removable dust reservoir). I've tried using a bag, and never got back to the bag-less configuration, things are so much better: way more power, takes ages to fill the bag, no filters to clean.
So, I found that the whole bag-less "revolution" is strongly driven by the marketing and commercial efforts instead of a real technological advancement. I find that Dyson started this bag-less, mass-market phenomenon, strongly overplaying the advantages of their solution. The other companies try to align by proposing the same class of products and everybody acts without any real concern for the actual needs or experience of the customers. (Even if the marketing says otherwise).
However, I like the Dyson Blade hand dryer. I don't know if it's much more expensive than other devices and I hope that my airport taxes ticket money doesn't go straight to re-equipping bathrooms, but I like it.