whats the hurry man.. :p.. you dont want to join the DBNC slogan ..??
Besides above i'd say that Gli will always remain superior and everyone knows that so you should also remember that.. City still cant meet up with Gli (my neutral opinion).
Xli will be bought by many commercial agencies in addition to usual customers + company cars, lastly its lesser price than its compatriot models will make it eligible for the largest circle of potential buyers therefore, i think Xli will sell BEST, as a car Gli has to be the BEST among the three and if you just want to feel that you're a features freak and small cars don't daunt you then City is BEST for you..
If price is NOT an issue than i dont think you have much choice left with you than Gli.. rest is upto you ..(Y)