Hi there, I suppose you are talking about NetJets in the US. Most NetJets discussions on this forum are about NetJets Europe which has very different terms and conditions.
I guess it depends on your personal situation. Are you a captain with NetJets? I guess you would be an F/O with Polar. Would you have to move?
What about job security? i don't know much about Polar but NetJets is here to stay.
Is there anything wrong with your present job, or is it just the heavy iron you are after?
My advise: Look at the total package including quality of live, pay, and job security.