Simply try to share my thoughts:
1. The basics of carpet cleaning is simple:
Soup it, brush it and dry it.
2. You can achieve these by doing it by hand.
3. What machine do best is brushing it better
than hand and dry it better than hand.
4. Once you understand this, the question is
what you really want to achieve? Clean a
wide area or simply spots?
5. For spots, you may be looking for a smaller
machine and not warry about it's capacities.
The narrower machine may works better and
may be more economically sound.
6. For area, you may be looking for a bigger
machine with larger water tanks and wider
foot print.