I would love to stay with AIM, but the writing is on the wall with the 7/1/10 PCI requirements. I have been told there is no way to be PCI bulletproof running zen cart with custom code (mods) on a shared server.

So SIM it is for better or for worse....

I guess SIM's "less secure" part is the fact that zc is forwarding the customer to another site, instead of securely transmitting data in the background? so I guess SIM is as secure as paypal is because they use the same method?