One advantage to the lever rifle over the AR or AK is that it does not have the "sinister black gun" appearance. Depending on what part of the country you are in, that may be something to consider.
I'd choose a Marlin over the Rossi, personally. If you get the Rossi you will likely find it is pretty rough out of the box but they can be slicked up and made better.
I agree with the reply that recommended a 20 inch barrel over the 24.