No idea, but I have one of the desk vacs too... 
I think that Numatic sells more vacuums because of the cute, cheeky little smile of the Henry (and other related Numatics), but I think it's only recently that they have actually gotten better, I've used Numatics in the past and always found them to be very weak with poor airflow, but the current motors they have (I have a pair of them, one in the Tristar and one unemployed and unable to find a job) are pretty powerful for their size and wattage, being double-veined and tapered, so, yeah, they are improving as the years go by... 
I just hope that TTI don't buy them out...
