Gosh, to be honest it's been so long that I can't even remember why I switched my store over. There is always some little glitch or feature difference between the two systems, whether it's stores, SMP or listing.
98% of my sales are to the U.S. and I got completely fed up with competing on an uneven playing field. Neat new features would be rolled out and you just couldn't use them if you listed on .ca.
One example I remember was the gift icon. The Christmas season after that first came out, it was only available to those who listed on .com. If you listed in a competitive category, where everyone displayed the gift icon, and you were listing on .ca you were out in the cold.
Another was with SMP. When they first rolled out the ability to combine invoicing on multiple purchases, it wouldn't work if you had a .ca SMP account. It took months before that became available.
Not the greatest examples, but just a couple of many I've found over the years. When I closed my store down for vacation two summers ago, I closed it and re-opened on .com.
I switched my SMP account to .com too. HOWEVER, IF YOU USE THE AUTOMATIC GST TAX FEATURE ON SMP you will NOT be able to automatically apply Canadian taxes on .com SMP. I live in Ontario and have to apply PST here anyway so I have always sent out all my invoices manually.

Monique
