Songhai are, in my head, possibly the most "underrated" civ, in that they can be a ton of fun, make tons of money, are great at fighting, make filling out Honor worthwhile, and yet are rarely discussed. In many ways, they're basically a version of Assyria that's less flashy and way more dependable (also, in many ways, like a more-dependable version of Spain, for that matter.)
What I mean to say is that they simply will get early money, for doing stuff you want to do anyway, and a lot of it. Assyria might get a tech for taking a city, but likely not. Songhai will get tons of cash. Spain may find an early wonder and get all the cash for an early settler. Songhai will find numerous Barb camps and get that gold. I'm no expert at high-difficulty strategies, but it seems to me that Songhai fits them better than most civs do. It's just Vanilla and was never sexy, plus it's not Arabia or Mongolia or any of the other specialized ones.
Still, if you saw a DLC come out today that gave triple gold for taking barb camps and other civs cities, and it also gave units automatic Amphibious + War Canoe, and their temples came with +2 Culture, wouldn't you be excited?
Songhai is worth a try, is all I'm saying. They've recently become one of my favorites.
