You can use the Sony with a Mac. You just can't use the Sony eBook Store. And, not being in the US or Canada you can't use that anyway. If you do plan to read DRMed books you will need to get access to a Windows PC to just register the Sony to your Adobe ID. Once you do that you are fine with the Mac.
That said, of the devices you listed only the CyBook is for sale now. There is also the BeBook.