Hoover F5914900 vs F7412900
images from manufacturer

SpinScrub:
The F5914900 equips with SpinScrub 50 whereas the F7412900 features SpinScrub 60.
The SpinScrub 60 has six rotating brushes in the nozzle, the sixth brush provides 20% more cleaning action in a single pass than the five-brush model, thus it gets the job done more quickly.

Edge Cleaning:
The F7412900 features edge cleaning bristles on both sides of the nozzle to help remove dirt and debris near baseboards, while the F5914900 has no edge cleaners.

Nozzle Width: The F7412900 has a wider nozzle.
The F5914900 has a nozzle width of 11.25 inches while the F7412900 has 13 inches.

Weight:
The F5914900 weighs 20 pounds while the F7412900 weighs 27 pounds.

Tank Capacity:
The F5914900 has a tank capacity of 133 ounces while it is 128 ounces on F7412900.

Location of ON/OFF Control:
The ON/OFF control on F5914900 is a foot pedal that is located on its left side, while the ON/OFF switch on F7412900 is located on the handle where you can easily get with your fingertips.

Price: The F7412900 is more expensive.
The F5914900 is priced at $169.99 at hoover.com while the F7412900 is priced at $199.99 (prices checked on July 19, 2013).

The similarities:
They have 12-amp motor, 8 ft hose, 20 ft cord, dual tanks, heated cleaning feature to dry faster, SpinScrub Powered Hand Tool for cleaning upholstery and stairs, 3 speed brushroll control, brushes can be detached for rinsing, backed up with one year limited warranty.

You can download manuals to learn more:
F5914900 manual: http://hoover.com/file/604/
F7412900 manual: http://hoover.com/file/593/

If you know more difference between Hoover F7412900 and F5914900, please share here, thank you.