64-bit compatible?

Yes. Both versions work. However you'll need to be careful to install the 64-bit build of Eraser for your Explorer context menu to appear.
am I given a choice of whether to install 32-bit or 64-bit when installing Eraser from the "standard" download? How to I get a 64-bit installation package???
Oh, right. Now the standard installation files automatically pick the correct version to install so don't worry.