Knowing which type of floor you wish to clean is an important first step to choose the right vacuum. If all you have to clean is smooth surfaces without rugs or carpets, then it's best to use the bare floor tool type of canister. Things become more demanding with different surfaces with viscous objects.
Turbo power nozzle can perform well for natural fibers and pet hair that crop up in carpets and rugs. Canister vacuum with turbo type tool should be used for scatter rugs and low pile wall-to-wall carpeting. Canister models often come with three standard stools, an upholstery / furniture tool, a crevice and a dusting tool. Check if those tools come with the vacuum before you buy though.
Next comes the second factor. Ease of use. A vacuum provides convenient, but if it is hard to use, it ruins the main purpose of using one. But even that varies from one individual to another because as you become familiar with your tool, it may give you more power than other models. As with the other factors, easy of use is also a matter of personal preference.
If you really want to get into details, there are at least a dozen more factors to consider upfront. You might have preferences towards a certain brand. Quality and strength are something you should not compromise. Other things, in no particular order, are noise level, capacity, storage, and whether you want a bag or bagless model.
Beyond that, you might want to pay attention to small details like whether it has retractable cord, various indicators for bag change, filter change or dirt alerts. I know people who insist on these features. Not that they are utmost important, but again, they are nice to have. Who knows, some of these may eventually become your favorite after some time. This is why I always tell people there is no such thing as the best vacuum cleaner.
When it comes to price, expect to pay slightly more than an upright vacuum cleaner of similar quality. However, if easy maneuverability Pulse bag filter is so important to you, don't compromise just because of this. It also takes no more than four cubic feet of space to storage space, which is a major plus for many people.
Thanks to the Internet, you can now browse through different models and spend all the time you have to choose the most valuable vacuum your budget can afford. My last advice is this. While it can be costly, quality vacuum will last for many years and even decades.