Some people struggle giving compliments.
They might be praising you behind your back but to your face might be a bridge too far.
I think when it comes to these people, you need to look for other signals to gauge your performance.
Signals such as:
Do they forward your presentation onto their superiors?
Do they come back for second helpings?
Do they inquire about chapter 2?
I think the above actions speak louder than any honest opinions hidden by politeness.
Thomas Duggan 