i happened to like civ 4 best. civ 5 is remarkably buggy (even after one patch-- the developers are promising MULTIPLE patches, too).
it's also been amazingly dumbed down-- it looks more like the "civ revolution" for console than the old civ series. for instance, the "one unit per hex" idea sounds very interesting but the AI doesn't know how to play with it. for that matter, combat is boring because all you do is build about eight or nine units (each of which takes 20+ turns to build), the whole game (given the hex limitation there's no point in building a ton at once; you can't use them). you might build six, seven cities at most, too.
the AI is also incompetent in a million other ways; for instance, on "king" level (third-highest) i had modern tanks while the AI was still using spearmen and archers...
economy is also hard to control, and just revolves around getting more resources. and you don't get a good feel for the "age".
i'd suggest you wait another six months, and then it might have been patched up to the point where it might be fun.