Hoover is better than Bissell....IMO. I know from experience. I own a Bissell, but borrowed the Hoover. I prefer the Hoover. Separate tanks is a key.
Stanley Steamer My wife is Latina. First order of our house, tile no carpet, woman loves clorox and pine-sol. I keep sayin' those are toxic used together, she don't care.
For getting spots off either carpet or upholstery "Blue Coral Upholstery Cleaner" is the best. It's a foam in an aerosol can. You'll find in on Ebay, Amazon and most retail stores.
I honestly don't know about the cleaning power side by side, but I did warranty work for both Hoover and Bissell and Hoover was not so good with warranty claims and Bissell was really good.