One big reason we went US was to avoid Bill 101 and all the language restrictions it entails. It was going to really slow us down. We also like the access to US capital that setting up in the States allows for.
An LLC is an amazing thing that we don't have in Canada. It provides limited liability while freeing you from the governance requirements that a corporation has. As a bootstrapped startup, it really sucks to have to deal with endless paperwork to keep your corporate veil in order.
Carl Mercier posted a really good blog entry from a local Quebec perspective, check it out:
http://blog.carlmercier.com/2011/08/29/us-incorporation-for-...
If you need any more details about how we set it up, send us a shout!
If you have the chance, could you do a blog/HN post about this? I'd love to understand how this is done as well.
One of the reasons we formed a US LLC (we're Canadians) when building Appifier was to work with Stripe. They're simply the best way we've found to handle online payments without the headache.
I can confirm that at the moment our experience (other than some foreign ownership headaches that were promptly resolved by their support staff) has been entirely positive. Integration was a breeze and the reporting is top notch.
Best of luck!