Is there a significant difference in flavour between real Mirin and Mirin-like products? I read everywhere that there are generally two types of the sweet cooking wine mirin: 

A) the real, hon mirin, a sweet rice wine with 14 % vol. alcohol 

B) the ersatz, or shin mirin / mirin fu, with less than 1 % vol. alcohol.

I'd like to know if it makes a significant difference in flavours or otherwise if one uses the ersatz mirin instead of the 'real stuff', e.g., for sushi rice or other dishes. Is 'hon mirin' the first choice among the Japanese?
I used hon-mirin exclusively when I lived in Japan, simply because it tasted better. 

My Japanese neighbor was surprised that I could tell the difference, and confessed (somewhat embarrassedly) that she used aji-mirin since her family couldn't tell the difference. 

However, I cannot buy hon-mirin in the US (I'm not 21, and hon-mirin is sold as wine while aji-mirin is cooking wine) so I've been using aji-mirin without detrimental effect.