I haven't used the Elan 7, but I considered it before buying my A2e and EOS 5. I felt I got more of my money's worth, even though they weren't new.
The EOS5/A2e has more coverage in the viewfinder and a faster top shutter (1/8000 vs. 1/4000) than the Elan 7. They both have DOF preview and mirror lock-up. The Elan has a newer metering system, but I've never had a problem with the EOS5/A2e. The vertical grip on the Elan 7 can use 4 AA batteries, but it looks like it's a bit clunkier than the one for the EOS5/A2e.
The EOS5/A2e also has 5 fps vs. 4fps for the Elan, more custom functions, and faster flash sync (1/200 vs 1/125), and spot metering.
One of the biggest reasons I picked the EOS5/A2e over the Elan 7 is because they went to using the flash for AF assist in the 7. The red lamp on the older Elan and the EOS5/A2e doesn't blind people or alert them when you are taking a picture in low light. Sure, it blinks a little, but it doesn't grab their attention like that damn headlight. Since a lot of my pictures involve low-light situations, this was of major importance to me. The brighter viewfinder was also important to me for this reason.
The Elan 7 seems to win out when using flash, but I rarely do.
Here's a comparison if you want to see how they fair in what is important to you. If you like the EOS sytem, I think they are both good choices.