It's fine, ed signifies the type of glass used to improve image quality in a lens, while a D 'chip' is what transfers lighting/flash data to the camera. A 'D' version of a lens would be a later installment as opposed to a non-D AF lens. Hope that helps.
I have and will still use a large inventory of Canon gear. My main rig is a MarkIIN, 70-200 f2.8, and a100-400L . Canon has not let me down in any way and I will continue to use it, but the D3 in low light is going to get a work out as this time of year most of the rodeos I do are going to be in the late afternoon to evening range.