It will be different.
The following comments are sweeping generalizations, and do not apply to individuals. Any given individual could be the opposite of my description or expectation ...
My experience is that undergrads are less focussed, harder to engage, demand more instant feedback, and lack motivation. They are are also more willing to learn, less indoctrinated with how things "should" be, and more adaptable.
My experience is that post-grads are more focussed, better motivated, clearer in their objectives, and more able to look at the big picture and delay gratification. They also tend to have more knowledge, and perhaps becuase of that sometimes they might feel that they know better, and not really believe what you tell them.
My expectation is that your approach will need to adapt, but that anyone who comes to you to learn should be able to be taught. But do you want to teach them? I don't think so. I think that any entrepreneur that has a chance of succeeding won't be taught.
You need to give them the opportunity to learn.
Patrick White: 'I forgot what I was taught. I only remember what I've learnt.'
B.F.Skinner: 'Education is what survives when what has been learned has been forgotten.'
Confucius: Tell me, and I will forget. Show me, and I may remember. Involve me, and I will understand.
But in the end, whether you stay teaching the undergrads or leave to teach the postgrads depends on how you feel about the opportunity to change.
Can't you do both?
As much as I think the Graduate students are more focused and eager to learn, I don't think you'll find the same enthusiasm or creativity as you may encounter with your undergrads.
I find Masters students to often operate very much by the book. Great managers. Not the greatest leaders. Of course that's not always the case, but many students go back to grad school because they're not exactly sure what they want to be doing.
If I were in your shoes, I would take the Top 10% of an undergrad class over the Top 25% of a graduate class in terms of what would motivate me to teach.
Best of luck either way!
Will not engage in the debate on teach/born entrepreneurs.
I would have quoted Piaget and Papert on learning.
The point on willingness to change is in fact the real issue. Trying to determine if the motivations are correctly assessed.