ECT was a life-saver for my MIL. She was so severely depressed she was catatonic and her speech was very disorganized. She was bipolar and had ups and downs for years along with substance abuse, but she was a wonderful woman.
After only a few ECT sessions, she was back. I'll never forget how her sons described her eyes -- they kept saying that they could tell she was back because they could see her in her eyes again.
She did have some memory loss (primarily lost memories about the past, not skills-based memories). I recognize how distressing it must be to look at a family photo and not remember the incident, but, frankly, the trade-off of lost memories for lifting the crippling depression was well-worthwhile.
Basically, in terms of skills-based memory loss, everything she was able to do before the depression, she was able to do after ECT.
I never would have believed how effective ECT could be if I hadn't seen the difference with my own eyes.