No experience with the Lancer but the Corolla has limited space for the rear passengers. Overall performance is okay and parts for both cars are easily available. I think the Lancer is more prone to kalampag though if i were to look at the history of both carmakers.
2001 Lancer GLX
1.5L 4G15 (i think) engine. it is carbureted though. so not really fuel efficient. not the top line model. i would consider the GLS better. as it is 1.6L EFI engine and has more features.
it (GLS) has 15" wheels compared with 14inchers of the GLX. 4w disc brakes, power antenna, better HU, full size headrest, ABS, Airbags etc that are missing in the GLX variant.
1999 Corolla GLi
fuel efficient 1.6L EFI engine, good features but still lagging compared with rivals of same year. a safer choice for me.