I think that it's better to be honest because you will feel free and not under the pressure of lie,  when you honest you shouldn't think how to make speach  sounds more like true.

but it depends on person 

I agree with you. But I think it depends of the company but too from the country where a person live. I live in Italy and if you're honest person is very difficult grow and to have opportunities.

I think,  in general the best way is to be dishonest but sly.

Sometimes instead is better to be honest with the honest people.You'll have positive return.

This might apply to a huge number of situation in life...

I think it all depends on the company you work (or are supposed to work) for, and how honest/dishonest are the heads of its departments (and so on with the lower levels). If you end up in a company where most of the people in there gained position through dishonest behaviours, they'll be likely to see employees who are alike as better employees and reward them.

Otherwise, if the executives share with you respect for colleagues and clients, you'll have positive returns in career.