I applied my Canadian PR a year ago as backup to US GC. Fortunately, my US GC and Canadian PR both got approved at same time. I already have US GC in my hand however I still need to land Canada for my PR card.

As Himalaya178, mentioned above, it is almost impossible to maintain both sides' PR. I went through couple of immigration web sites and forums. Honestly, different people have different views, whether you can keep both PR or not.

However, if you go through USCIS web sites

 (http://www.uscis.gov/portal/site/uscis/menuitem.5af9bb95919f35e66f614176543f6d1a/?vgnextoid=fe17e6b0eb13d010VgnVCM10000048f3d6a1RCRD&vgnextchannel=4f719c7755cb9010VgnVCM10000045f3d6a1RCRD) Maintaining Permanent Residence section,

The first clause clearly says, you are not supposed to move permanently to different country intending to become permanent residence. However, it does not say whether you are allowed to have PR from different country.

If you ask me my personal view -

I have already booked my ticket to Buffalo, NY and planning to cross border on the same day. As per my visa, I have to be in Canada by June 12th. I am doing this to be in a safe side. Because; I heard a humor that you cannot quit your sponsoring company, at least for 6 months even if you have GC card in your hand.

I am still waiting for some good suggestions.

Thanks

-          NF