Yeah, America is balanced. Fair UU but come too late into the game, with B-17 being there just to finish the game (more or less).
UA +1 sight is excellent, while title buying isn't that impressive. It can help when you really need to buy this or that title to prevent AI from settling, but otherwise, nothing special. Not bad, just not overall impressive.
I'll start with Rome, since it was my first civ I picked in CiV
(and 4 if I remember correctly)
UA: Glory of Rome - 25% production toward buildings already built in Rome (capital)
Good strong UA that is very useful during the entire game. +25% bonus production helps Rome quickly establish infrastructure in their cities. Balanced by terrain and city placement. No amount of +% will help you out if you have terrible base production.
UU: Legion - fair UU, but nothing special combat wise. Can build roads and forts, saving precious times worker will use to build roads. Works well with UA, because Legions can help establish roads while workers are busy improving titles like farms\mines\luxuries. If give some promotion, they can survive until they are replaced by Longswords.
Fair unit if you ask me. Not that impressive on paper, but lot better in practice.
UU: Balista - not that great UU. It's slightly buffed catapult. Really nothing to write about. It will be used to weaken city before Legions finish the job. Composite Bows will usually be needed to protect Balistas.
Overall: Rome has very strong UA, one fair UU unit and one "meh" UU unit. Fairly Balanced civ if you ask me.
and I'll do one more civ, since I know it's gonna be bashed for no real reason:
Songhai.
UA: River Warlord - Triple gold from barb camps and pillaged cities. Embarked units can defend themselves.
Askia's UA isn't that terrible as people make it out to be. Check raging barbs and you'll have enough camps to pillage. You'll get 75 gold per each. Do several barb camps and you'll have enough gold to rush buy buildings or more units to do more barb hunts. Works well with Honor. Pillaging cities works even better, you'll often get 300-600 gold, or even more if you attack Tall Empires.
Other part of the UA isn't that great, because it's situational and no one in their right mind will do "water invasion". Why, when you can just attack from land?
UU: Mandekalu cavalry - on paper not that impressive, but they are quick to build and have no penalty attacking cities, which means Songhai can have highly mobile forces to raid and pillage.
UB: Mud pyramid mosque gives 2 Faith + 2 Culture and cost no gold to maintain. What more do you need???
boost it with religion (+2 Happiness and +2 Culture) and you'll have Mini World Wonder that cost no gold and is built for 100 hammers.
Overall: Songhai are close to balanced. UU and UB are strong, UA could be little better. It's not terrible, but it requires player to be more active and will not suit people who like to turtle. Too bad Askia AI is clueless and always fails to do anything.