Daewoo is tiger of long routes :). Having said that, if you maintain your car in good condition, it won't let you down. The people who are scaring you by saying that this car is not reliable, did they ever have any chance to even sit in it? Can you ask anyone of them do they find any EFi engine mechanic for any other car on long routes?
Regarding the computer, I have seen just few malfunctioning daewoo ECMs. There is only one drawback in the placement of ECM though, the radio antenna hole is just above the ECM housing, and if you have some leakage in the hole and/or antenna it self, water can enter the ECM.