THE QUESTION of which type of vacuum is best—canister or upright, bagged or bagless, corded or cordless—remains a polarizing one. Just watch couples in the appliance section of Best Buy. Or read the comments on the community-driven website Reddit, where an online chat with Brian Driscoll—a vacuum repairman who manages a shop in Fort Worth, Tex.—was more popular than similar Reddit Q&As with Arnold Schwarzenegger and Bill Murray.

Whatever your style of choice, with allergy season here, it’s worth remembering that a good...