There are many satisfied users of both makes. If you haven't made up your mind for a particular make then best thing is to take a test drive of both makes and then decide yourself.
And one member here said that GLi wobbles at the 120 km/hr or more so there is no such issue like that. I have drove one GLi at more than 160 km/hr and one XLi till 120 km/hr. there was no such issue. Even the GLi alignment was a little bit out. So either there is something wrong with that member's car or the car which I drove was the best piece made by IMC. 
As far as Nissan Sunny is concerned. Its a great car but the only reason people don't buy it here is the resale value. Otherwise if you compare the features with XLi/GLi and City, it has far more options. If resale is not an issue than you can go for Nissan also.
But do take a test drive of all the cars under consideration before deciding.
Best of luck 
