I started to seriously consider ECT for a while, and did a lot of online research through organizations like NIMH and the Mayo Clinic. It does sound terrifying, but according to my research, it can be quite successful, and it is very safe (not the horror movie stuff of the 50's or Cuckoo's Next or anything like that!) The only frustrating side effect I've read or heard about is some memory loss. Not like amnesia, but more like I can't remember if I read this book (even though you've read it twice). However, this seems to be temporary.
I will say that there are a lot of anti-psychiatry groups out there that are spreading the "horror myths" about ECT, so research through reputable sources, and bring questions to your doc if this is something you are thinking about.
"Sanity is a cozy lie." ~ Susan Sontag