Depends on whether you want to go in town (which means Chinatown)or into the 'burbs. The Big Three in Chinatown tend to be Imperial Teahouse, Dynasty, and China Pearl. There's a few others too. Just go where the lines are. In the suburbs, two of the best are both North and serve all you can eat buffet: Far East Cafe in Woburn, and Lin Garden in Dracut.