It depends how experienced the unit is, how much gold you have or can obtain quickly, and whether you have anything that affects unit upgrade costs.

Gold was never really that hugely useful in all the other Civ games in the first place (with the possible exception of Alpha Centauri). For the most part you just used it to pay for maintenance, upgrade your units (unless you had Leo's Workshop in Civ 2, in which case you don't even do that), bribing enemy units, or rush-buy stuff. Civ 4 just takes out bribes and rush-buys (for most of the game anyway).

Admittedly, rush-buy can be powerful. But Civ 2 simply isn't geared to give you an economy that is massively gold-centric enough to truly allow a gold-based economy to function (by buying rather than building infrastructure) and winning wars (by bribing the enemy army).

With Alpha Centauri though... the sky's the limit. This is the kind of game whose economy can get so broken that I once beat a CPU opponent to a Secret Project (wonder of the world) five consecutive times over five consecutive turns... when the CPU was one turn away from finishing the project while I was starting from scratch in each of those five turns

Gold/Credits are very useful in Alpha Centauri. It was actually a bit of an adjustment when I first played Civ III and found out that gold can't buy you everything, like it can in SMAC.

And the proto-typing was awesome. Where would I be on islands maps without my flying colony pods?

---

"You can't hammer tin into iron, no matter how hard you beat it, but that doesn't mean that tin is worthless."
-Jon Snow, A Game of Thrones

"I prefer my history dead. The dead sort is written in ink, the living in blood."
-Rodrik Greyjoy, A Song of Ice and Fire

or stealth ships? or buggy artillery? the prorotyping rules were awesome, as was the terraforming.

shit, I'm going to have to start this game up again...

---

"Aid, trade, green technology and peace." - Hans Rosling.
"Market forces are a good servant but a poor master." - Zaune