Question: what are the top cordless vacuum cleaners?
Answer: Upgrade pick. Dyson V11 Torque Drive. In a class of its own. The flagship Dyson automatically adjusts suction according to the surface it's on, and it cleans carpets better than even some plug-ins. ... 
Also great. Shark Ion F80 MultiFlex. For Dyson haters. ... 
Budget pick. Hoover Linx. Lower price, for easy jobs.