I would love to hear from other people here but I tried it for a while and dropped my subscription. For short things it was nice, but the larger the suggestion the worst it got. I found myself constantly mentally debugging the output it suggested, I do not know if it was faster but I was mentally exhausted by it, unable to go for long periods of time.
Dumb code completion is predictable, I know I'll need to press down three times before its even shown to me, enabling me to think forward. With "smart" code completion I need to constantly stop my train of thought to process what ever it throws at me.
I even tried to just trust the system, playing it fast and loose, not double checking everything, but then it just produced bugs.
I'm developer with 16 years of experience, currently working mainly with python for API work.
I'd love to hear accounts of other people, please add your background if you feel comfortable. I want to see if there is some correlation to experience, programming languages or use cases.