If the 3 is Japan based, get the 3. You'd have more fun with it. If the 3 is American based, get the Fit. You'd have a car that would actually work.
(I don't remember which ones are Ford based and which ones were strictly Mazda based.)
FLY PLEASE READ THIS POST TO VERIFY THAT FORD AND MAZDA USE EACH OTHERS PARTS AND PAY UP BISH!