"Just, wow!"
I have now hoovered my mattress a few times and done two more for relatives. At first glance, it seemed like nothing had collected in the dust collector but once I dismantled it, a good tablespoon of dust and fluff-like stuff came out of the filter, even after a few goes! I found it easy to use, although understandable requires some patience in slowly pulling it across the mattress. I also found the dust collector unit nearly impossible to remove when I first got it, but I used a little silicone spray and it's slid out beautifully ever since. The cable is also generously long too. Impressive!