I worked in a hotel that all Sebo X series machines. Carpets always looked disgraceful!! Tons of built up around the edges and main rugs weren't even that great looking. I had my fair chance of using several of them at different points checking bags and ensuring brush rolls were clean too. I wasn't happy with performance of any.
At another collectors house about a year ago, he had a Sebo Navy blue with yellow, auto height adjuster. Automatic height adjuster takes a very long time to adjust between surfaces!! The 4 of us present were not happy with air flow from hose or the agitator. Out of about 10- 15 machines that we played with that night, the Sebo groomed the carpet the worst!!!
From what it sounds like the UK does not have access to Tacony machines Riccar or Simplicity line!! The Riccar/ Simplicity Tandem Air Machines are extremely durable, awesome agitation and extreme air flow. Compared to what the Sebo picked up, you'd be looking at probably 1.5 full bags with the Tacony!!
Kirbys don't work for me. I've tried several including: several G4's, Ultimate G Diamond, G6 2000 special, Sentria and Sentria II. Grooming is unimpressive to me. Extremely awkward manuevering, awkward self propel system. Long hose for attachments but the hose broke twice trying to use it with wands to clean bare floors and I had to find a generic bare floor brush to use, cause I thought the Kirby ones were awful. In Filter Queen demos, I've found some Kirby owners that like them but many Kirby owners that do not like them. The Kirby sales tactics are very harsh and once the paperwork is signed then the visualizer is removed, the paperbag and cloth bag setup is installed making a clogging air polluter. Tons of dust escapes those cloth bags. Find a bright light like one used by Kirby, Filter Queen, Rainbow and others with a light bright enough to see dust in the air. Cloth bags should be able to remove dirt that the human eye can't see, however evidence shows they spew out a great amount of visible dirt!!!!