How large is your cleaning area? If you're cleaning a large space, such as a great room, a corded stick vac may be inconvenient. That said, you'll want a cordless stick vacuum with the longest run-time. Alternatively, you can purchase a backup battery to continue cleaning after you've drained the first battery.
Where will you store your stick vac? If you have a small closet where you'll store your stick vac, consider a model with a fold-down handle for easy storage. Another consideration in choosing a cordless model -- does your storage area have an electrical outlet for charging the battery?
What type of flooring do you have? Stick vacuums are, generally, best on hard floors. There are a few models that perform well on carpets because they have a roll brush that combs through carpet fibers for dirt and debris.
Do you need to clean something other than floors? If you like to use a lightweight vacuum for cleaning nooks and crannies, baseboards, or other tight spaces, crevice tools and wand attachments can prove useful. If your regular vacuum already has these attachments, it's not as big an issue if you don't mind hauling it out.
Stick vacuums are generally pretty cheap to operate. Most have filters, but the majority of stick vac filters are washable and can be used throughout the life of the vacuum. Constant battery charging is one issue that crops up in reviews, although it's not typically significant enough to create a noticeable difference in a homeowner's electric bill. Still, it's worth looking at ways to avoid excessive energy use -- keeping the Lithium-ion battery off its charger when storing, both to avoid unnecessary energy use and to extend the useable life of the battery itself.
Consumers are expecting more from their stick vacs based on technological advancements in other home appliance areas. For instance, smartphones have tiny batteries that function for hours, yet most stick vacs still have an average of 15 to 20 minutes of run-time. That's starting to change, as more stick vacs are emerging with capabilities to rival that of the standard upright or canister vacuum. Attachments, longer run-times and exceptional carpet-cleaning capabilities are just a few of the features new stick vacs are offering. The G-Tech AirRam (Est. $350), for instance, is said to be equally as powerful as a standard vacuum cleaner and capable of handling the full vacuuming responsibility for the average home.