I have a SFE in my reef tank, and he has NEVER gone after anything intentionally. As stated, they occasionally make a grab for something, but it is just because they are blind.
I have a small tang, and some chromis, and the tang pushes the eel around all the time, and the SFE is about 24' (started at about 8').
Personally, and this is only in my very limited experience, they are great additions to a reef tank...every time i go diving I see an eel in the reef, so they are a natural part of the ecosystem. However I would have two warnings:
1. They knock stuff over when they are slithering around. This includes corals, and entire portions of live rock, so make sure everything is well placed and secured. They like to borrow through the sand under the rocks...so be careful!
2. They are dirty eaters, and they like to eat...so make sure you filtration is good enough to handle it.
Other than that, they are great...and there is something really cool abnout seeing an eel stick its head out of a rock in between a big lump of coral with a cleaner shrimp cleaning out the inside of his mouth! It makes you realize that everything in the system is working / living together.
HTH
Stewart