Vacuum cleaner suitable to your environment
Appliances that you will use for your home or for your office should be such that it matches the surrounding environment in existence there. For example, you may have a large house where you should be using a vacuum with large head. Some models are now having heads that are larger by 25% to their original heads. The advantages are that such vacuum cleaner will reduce the time consumed for cleaning to a great extent. The miele vacuums have many models that come in this category.
Similarly, your requirement of vacuum cleaner will be completely different if you have deep pile carpets. In such case you will opt for a cleaner that has extra power with a rotating brush either in built or as accessory. Such extra accessories will be turbo brush or nozzle having their own power supply. The Miele S5 and most of the dyson vacuum cleaners support this feature.
In case you are having a different floor type, your requirement will be a versatile machine. Such machine should have carpet height adjustment or floating head. It adjusts to the carpet pile. On the other hand for houses with long flights of stairs, cylinder cleaner attached to a long hose would be ideal. Several such models are available in the series of dyson vacuum as well as the miele vacuum cleaners. The only thing to look into is the weight of the machine since you may have to carry it upstairs for cleaning.