I've played Civ Revolution, but I want to buy a PC version. Should I get Civ IV or V?

I LOVE Civilization Revolution on the PS3, but I want to get a version that's more complex, which would be either 4 or 5. I know Civ 4 is older but i heard both are great. Which should i get? Thank you.I've played Civ Revolution, but I want to buy a PC version. Should I get Civ IV or V?
I have played both. Civ V takes it to another level, but if you are looking to save some money and are not entirely certain the PC version is going to be all you want it to be, Civ IV is a lot cheaper because it is older, and the graphics are just as excellent (IMO). I prefer the gameplay controls (zooming, movement) of Civ IV, personally, but that is entirely subjective as a good friend of mine says HE prefers them on V, so...



The games are really quite close in comparison.