Godfather isn't as expansive as GTA, but it excels in other ways. You can shape and customize your thug, and the supporting characters you'll meet are all guided by Sims-like "aspirations" (like the aspiration to not get shot, say). And while the cars are limited to a handful of period-appropriate models, they're fast and fun to drive. Also, shooutouts are much better than in GTA; you won't last long without learning to hide behind cover, and the auto-aiming feature is very good about targeting the nearest armed threat. And once you're locked on, you can easily move your crosshairs to shoot hands, kneecaps or heads.
If shooting isn't your style, you can always just pound your enemies with the Fight Night-like punching controls. Nudge the mouse up for a jab (or flick the right thumbstick, if you're using a joypad), for example, or pull it back and forth for uppercuts. You can also use this system to grab an opponent and smack them against walls, into furniture or over ledges, or just execute them with a quick neck twist or slow strangulation. It takes a little practice, but the control scheme is responsive and well-suited for kicking mobster ass.
The PC version looks much better than its console counterparts, and unlike most console-to-PC ports, it's actually designed for use with a mouse. If joypads are more your thing, though, the game can use most peripherals seamlessly.