Depends whether you like the 'westernised chinese food' or proper chinese food. You can often tell the best chinese restaurants by seeing chinese families eating in them.
Best ones are The Imperial, The Good World and The New Millenium...all in town. All three of these restaurants do a Dim Sum menu which is traditional Chinese afternoon tea type food. (ask for the chinese dim sum menu and give it a go!)....Dim sum often required well trained chefs...and hence for that reason alone these restaurants you can say the food is being cooked by trained chefs.
There are a number of good chinese restaurants in the north side of town especially The China House and my favourite the Peking house on Parnell st. Believe me once you try these authentic restaurants, you'll not step into a take away or a westernised chinese ever again!
Most take aways/ westernised Chinese restaurants are family run and so the chefs who aren't trained.