I've been coming to Xi'an for 2 months/year for about 6 years now. Colabo used to be one of the best restaurants in the city, but that was when there was little competition. The food and dining room are average (great for Western food in Xi'an). The service is friendly, but inflexible and lazy. At my last visit, my friend and I ordered the exact same pasta at the same time. The two orders arrived 30 minutes apart. Maybe it's their strategy - I ended up eating extra bread while I waited, which they charged me for. I tried to change my order to something faster, but they told me it was impossible. My friend was Chinese and very proud to be taking me there, so I didn't want him to lose face by cancelling my order and complaining. Otherwise, there's no way I would have waited so long for 200g of pasta.
This restaurant would not survive amid experienced, professional competition.