Neil,
When you say you are a small carpet cleaning company, does that mean you are working with a limited budget?
If so then the Sebo duo would be good value for money.
If you were looking for something a little more heavy duty then an Enviro dri or Host machine would be the best option.
If you are young, fit & energetic, a carpet brush and alot of arm movements will get the job done just as good for about £18.00