Geo Metro engines and transmissions?

I want to buy a car and I've spotted a Geo Metro and a Pontiac Firefly. Both are 1993 model year and they have similar mileage. One of them has a 1.0L 3 cylinder engine and a manual transmission, the other a 1.3L 4 cylinder and an automatic transmission. Is there one of these combinations that is better or more reliable than the other? Sure the manual would be better on gas, but I'm wondering whether the 4-cyl. engine may be more reliable.