Invest in an envirodri Russ - most of the cleaning is done with the pre spray and agitation. The envirodri is a massive leap up in performance from a sebo, I've used both.
The extraction/rinse machine is just that, a rinse machine, to extract all the crap that you have loosened with the pre spray and churned up to the surface with the crb machine.
Personally, I think a rotary is overkill on most domestic carpets, but I do occasionally use an Oreck Orbitor.