"Tempered optimism" -- that's what US companies are feeling when it comes to China, according to a just-released annual survey. First for some optimism: 90% of companies said their China operations are profitable, the highest number ever to report that, according to the survey released on Oct 10. And while down from 67% last year, more than one-half of companies still plan to increase the resources they put into China. The biggest challenge: cost increases, particularly for labor -- that's up from last year, when it was only the fourth-biggest concern for companies. After costs, the second-largest concern was competition from Chinese companies. And while some competition was the natural result of China's slowing economy, it also stemmed from protectionist measures favoring local players, said the American investors.