Henry looks like a toy and it's marketed like a toy, but it's a very good vacuum cleaner. I was in two minds about getting one, but it just so happened that I got £100 of Nectar points from work when I was looking for a new vaccum cleaner and Henry was selling for £100 in Argos at the time.
It's the most effective vacuum cleaner I've ever used. I've got the standard head, but it works fine for dragging hair out of the carpet.
It's by far the quietest one I've used (the fan is much larger than other vacuum cleaners, so it spins much more slowly for the same airflow).
It has enough reach to do my stairs easily - most of them when I'm doing downstairs and the top few when I'm doing upstairs. The reach also means that you don't need to move the vacuum cleaner much.
The bags are huge and cheap. I was forever emptying the bagless I had before and it was a bit of a bother. Swapping bags is easier and I have to do it far less often. The bags are ~50p each and hold loads. I just bought 20 with the vacuum cleaner and that'll last a couple of years. HEPA filtration, too.
Can't fault it, not in the slightest.
I've just looked at the reviews on Amazon and found a 1 star review. So I looked at it and found why they rated it so low:
It's a good little cleaner - however for a 67-year-old with bad arthritis it was an expensive mistake. Good suction on it - too good really as it cements itself to the carpet! I tried it a couple of times but it aggravates the arthritis in my neck and lower back and I find it too hard work to operate
Which is a fair point if you have bad arthritis.
Miele is generally considered better, though. Henry is an industrial cleaner, designed primarily for heavy use on short pile or no pile. Miele is a domestic cleaner, designed primarily for home carpets.