i have never played GTA3, but this game is drawing a lot of comparisons between itself and that game.
so w/o having played GTA3, here is how i see Mafia:
1) i run i guess what is considered in the gaming world as an "out-dated rig." i have a Celeron 566 which is OC'd to 850. i have 512mg of RAM and a GeForce 2 card. all that said, i installed the game, changed the resolution to 1024x768 and let 'er rip. and guess what? game looks sharp and doesn't frame - at all. what's this mean for all you geeks running some of the top o' the line PCs? well, judging from what i have read, this game is simply gorgeous on GeForce 2100 and up cards. it looks good on my old tech, so i can see where they are coming from with that opinion.
2) i guess the merger (i.e. see Vivendi) between movies and games is almost complete. all big title games now start with "movie intro" including actors names, producers, directors, programmers, artist, etc and Mafia is no different. this intro is really nice. how nice? so nice that Illusion added an option in the menu to just play the intro, even though you get to watch it in game in the first chapter. i watched it twice. along with the visual intro is the audio intro: what can only be described as a "score" just like movies have. all in all - very impressive way to start a game.
3) there is a pre-game tutorial where you can try out all the usual moves you might need in game, from 3rd person movement to 3rd person driving. good little workout to teach you b/c if you are like me, the driving with a keyboard is going to take some getting used to.
4) then there is the game. i am only in chapter two, but so far the story is interesting...although i feel that i am really just working in a plan to learn the city right now before the real action starts. still, seems fun to me and i am interested in continuing play.
so far it's been real enjoyable. coupled with the reviews that are out there, i think it is going to be a real winner.
for more info: http://www.gamerankings.com/htmlpages2/4807.asp