I am Canadian as well. Make sure you surrender your TN I-94 when you travel to Canada. You can use the H1b record to enter US. there are two documents at the bottome of the I797 - one is the H1b record that you should keep it as a visa, the other is a so called I-94. the CBP officer may take the I-94 and ask you to fill out a regular white I-94 form. Just do whatever you are asked to do.
it's very convenient for Canadian to travel with H1b.