I had both the plug grafts and follicular unit transplants, and I can tell you there is a significant difference between what is seen and what isn't.
I had a number of procedures using the former method, primarily to hide each previous surgery. Maybe I was just sensitive, but I always felt people were looking at my hairline and thinking, "he had a hair transplant."
Luckily, I had enough donor hair to get a total of 2800 FUT over the past 15 months. I can honestly say that, while I notice a marked degree of fullness, I can't tell the native hairs from the transplanted. If I can't, I doubt anyone else can.
Do what others on this site have suggested: do your research, talk to a recommended surgeon, and proceed with confidence.
bb