Need a good Carpet Washer/Cleaner recommendation please

Hi, what a minefield. i have a filthy marked front room carpet, due to children and food, needless to say, and think its about time i bought a carpet washer that will restore my carpet to at least half decent.

But what to buy? what is a girl to choose? Bissell or Vax? and which model? i don't want to settle for cheaper one if it doesn't get down into the carpet as well as i'd have liked.

has anyone got one that they would care to recommend to me? cheaper the better, money is a bit of an object, but will consider anything if it does the job properly.

your advice is much appreciated. :j
thanks