un2114: Whats the difference between 3 and 4?
They look almost identical.
As said above, 4 is more scripted : you get numerous steps to reach your overall goal (although many of them are not mandatory, most will really help you to reach the endgoal), random sidequests (like exporting 500 rum bottles to the USSR) to get some bonus and give you some more concrete, immediate goals, many scripted events, etc... The result is that you always have something clear to do right now, while in T3 you are much more left to your own device.
As a result T3 feels more "sandbox" even in the main campaign, and is slightly more difficult.
other differences... Mmmh...
T3's humor revolves mostly around the comments of Jacinto, the local radio DJ. T4 ditches Jacinto (which is a shame, since the guy is really cool), but gives a face and a voice to the political factions in the island by introducing leaders for every one of them (Most of them pretty silly, but I like them)
T4 introduces ministers, but does not really do much with them.
The complete version of T4 has more buildings, but I kinda feel they are nicer looking in T3.
I know many people like the modern times stuff in T4 (didn't check them myself, I was too busy having fun with the original campaign)
The soundtrack of both games is nice, which is important since music is a big part of the Tropico experience. Although personally, I'm still a huge fan of the T1 soundtrack, by far the best of the lot.
Mmmh... And lots of small stuff, adjustments, added and removed content, etc... some of them good, others less so.
But yeah, overall, T3 and T4 are REALLY close. More like "T3 and T3.5", so feel free to test either of them.