I bought a miele s2110 a few months ago after owning another miele which was called a cat and dog vacuum which was excellent. Out of all the vacuum cleaners I've ever bought id recommend the miele s211o. It's very powerful and the suction is great. It picks up cat and dog hairs out of my carpets and gets into all the corners.
It's very useful on the stairs as I've never got on with upright vacuums for hoovering the stairs. The real miele brand bags are quite expensive but I think they are worth buying as I bought some other cheaper versions and the ones that I bought nearly all seem to burst once nearly full.
The tools are very handy for doing the furniture as well. I found you need to turn the power down when cleaning sustain items. It does not seem to ever lose its power even when it's full. I would recommend buying this one.