Hey,
I made the leap from Bell Mobility in the summer to Virgin. Quite honestly I love it.. the service is great (they use Bell's lines) and they have quite a few pay as you go options available. I love it as all the extras are free (call waiting, call display, voicemail etc) I also like how there payments last longer.
I'm not sure about rogers pay as you go, but bell has restrictions like lower denominations of money last less time, so if you use your phone rarely you can end up with a lot of money piled up on your phone. For virgin any amount lasts 4 months. Also you can check you balance right on your phone with just a clicik of a button, it displays on your phone, and you can add time with a card or if your credit card is on file with just a push of a button.
They also believe in keeping your phone number. So once you get a virgin phone you get a phone number and thats your number for as long as you are with them. So if you decide to upgrade to a better virgin phone the next month, no problem, it's all transferred over. None of that staying with the same phone, or being on a high paying plan to keep your number.
My only complaint is the service window is still growing. They still don't offer service in the states, but they said it is coming soon. ( I border hop for day trips frequently)