Just checked out the Revolution site...so apparently here's the difference:
Advantage II: Kills fleas and flea eggs.
Frontline Topspot: Kills fleas and ticks, but not eggs.
Frontline Plus: Kills fleas and flea eggs, and ticks.
Revolution: Kills fleas and flea eggs, heartworm, ear mites, hookworms and roundworms. Does not kill ticks for cats.
Depending on where you can find it online, they all are roughly around the same price. Advantage and Topspot run a bit cheaper than the Frontline Plus, and the Frontline Plus is a bit cheaper than the Revolution. But not enough to make a huge difference.
Choose the one that best meets your needs; Since Bandit is an indoor cat, we worry about fleas and ticks the most, and aren't concerned much with the other parasites. An outdoor cat should definitely have the Revolution, in my opinion. I would definitely not get the topspot because if you're already infested you need something that kills the flea eggs. The topspot should only be used as a preventive measure.