im do mine by myself with the hire ones, i think theyre great
i do mine every 3 months, its a bit pricey the first time u do it because u have to buy the shampoo and defoamer but they last a good 3-4 uses so now it only costs me about $35!! much cheaper than professional.
They can take some getting used to and they do use alot of water, but u can definetly see the results.
i get mine professionally cleaned once a year tho, im funny with carpet only because the kids play on the floor all the time! i recommened doing it urself but only if u can be bothered! also u have to wait for ur carpet to dry because theyre steam cleaners not dry cleaners so that might be something else u'll need to think about
Good luck