Those reviews by Ision are interesting reading and they do provide some fascinating insights into each specific civ. The problem with them, and any full dissection of any civ in a debate environment, is that the pros are always from the point of view of an ideal scenario and the cons are always from the point of view of an unideal scenario.
For example, one states Industrial is good when combined with a civ that starts with Pottery (for Granaries) permitting rapid early map expansion.
The next guy states that it's all very well having rapid expansion but it's all going to halt at size 6 anyway so it's not that much of an advantage.
So the first guy states that's why you build on Rivers.
Likewise...
The first guy states Expansionist is good for popping all those huts.
The second guy says what if its a map without huts or a high level where huts don't give much.
etc.
This leaves most of his reviews as guides as to how to best use the respective civ in the perfect scenario rather than a specific review of how the civ operates in a random setting. Guides are more useful than reviews but if someone was to attempt an accurate judgement of a civ's general worth then someone should create a specific 'average' map and then slowly work through all the civs to find out which ones had the best of it at which point etc.
The scenario I like to use the Americans for is one I thought long and hard about before I started my first 'Cheiftan and up' challenge. I went through all the civs one-by-one trying to work out which combination would best suit my scenario and Industrious/Expansionist just seemed most logical.
A Cheiftan and Up challenge is where I put every setting to Random except specifying a Tiny Pangea and then see how quickly I can achieve a Military Victory Condition, once the first level is complete using the Play Last World option and keeping all the settings the same except for changing the hardness setting to the next level up.
As Tricky states, the Americans are a good choice for such a scenario as they are Industrious, meaning speedy roads into enemy territory and rapid early gold/shield accumulation. The Expansionist trait is also good for jumping all the huts and doing some quick tech deals and since the aim is going to be to have victory before the Middle Ages even settle in then one is only really interested in acquiring the basic military techs of Warrior Code, The Wheel, Horseback Riding, Bronze/Iron Working and possibly Mathematics so getting these as soon as possible and then maximising Tax and minimising Science is ideal.
Also, as Tricky states, I have my biggest point scores from doing this.
By this method of play I'm not concerned about building anything at all except barracks and one Settler and one or two Workers, it's purely a short-term military Unit pump-station game.
I tend to quit at Monarch/Emperor level because the game tends to cease being a 'quick' game after that point. Cheiftan being about a 1 and a half hour game and Emperor about 4 and a half hours.
For my normal campaigns on big maps on Regent level I wont use the Americans just because they are so... boring... what with no cheap buildings, no extra gold squares to look at, no fancy UUs to peacock about with, no bonus techs and barely any historical arch-enemies to role-play with.
My criticism of the implementation of the Americans would be that they should get Factories and Off-Shore Platforms half-price. I feel sure this would have a lot more people raving about how cool they are and give them a greater sense of role-play in the civ world.