Great idea with only mediocre execution, however the replayability and online play make up for it's few short comings.
A few other things that are annoying are the AI, and the flaky alliances and treaties, for instance, as the US I decided to build an Anti-Missile Defense system which quickly led to me being kicked out of NATO and the entire world's relation status plummeting to red. Not something I would expect from a game that's main selling point is realism, but there are ways to work around this.
Another annoying aspect is sometime when declaring war on other countries, entire cluster **** of nations will declare war on you as well, even if they are not allied and even if their political ideology is completely different, not to mention how exactly does Sri Lanka land in New York City when it only has a couple hundred infantry units? They must be good swimmers or something.
Despite all these, and other factors SuperPower 2 can be quite enjoyable, although fans of RTS games such as Company of Heroes and other fast paced RTS style games with visual effects and story telling will probably not be impressed, fans of other games such as Hearts of Iron 2 and even some Total War fans may find themselves at home here.
The online community although sometimes a bit nuclear-trigger happy, (Korean players can sometimes join the game and start launching nukes without so much as saying a word....) can be enjoyable, and this is where the real game play really is, (since the AI is utter **** )Playing online with player established rules, and even some role playing can be refreshing. Having an arms race with a couple other players and making and breaking alliances can be fun for awhile, although in the end it usually comes down to who can click/steam roll the fastest and or shoot the most nukes.
In short, Superpower 2 is a great way to kill some time, but the game is by no means perfect, and it's appeal is only to a select audience of the RTS community.