If you know what you are doing, using correct cleaning products for the job, wand technique etc, then any machine will get more or less the same results, may take a little longer thats all.
Back to the original question regarding Leasing, if you have the funds i would try buy outright and avoid the monthly outgoings, Cleansmart seem to have some cracking deals on the Airflex range and if i was looking to purchase a porty then they would be my first port of call.
Mark