Both can get around 10 km/L in moderate city driving.

Sa Altis, common problems are - A-pillar rattles and a stubborn trunk release lever. I had these issues but they were quickly fixed with a trip to the casa.

No idea about Elantra problems since I don't own one. My friend though had suspension problems in his less-than-a-year-old Elantra, but I think it's a isolated case.

Between the two, I'd get an Elantra, change its rims, and add foglamps.