Not all bagless vacuum cleaners are the same. The type of separation system makes a big difference to the performance of the machine and the amount of filter maintenance required.
The history of vacuum cleaners in the UK dates back to the early 1900s. Hubert Cecil Booth started the first vacuum cleaner company in the UK, known as the British Vacuum Cleaner Company. It wasn't long however before William Henry Hoover, who had already experienced success with his vacuum cleaners in America, made headway in the vacuum cleaners market in the UK and overtook Booth.
A high wattage (input power) doesn't always mean better suction because the amount of this power that's turned into air watts (suction or output power) depends to some extent on the vacuum's design and efficiency.