Just for the record, when I say something, I am not like those annoying people who go, "I think I speak on behalf of everybody when I say..."
What I say, especially when it's concerning something as indefinable as a car's "specialness", is what I think, not implicitly extended to the whole world.
I was recently told by an Italian that it's weird that I like Alfa Romeo more than Ferrari or Lamborghini. When asked why he said so, he said because more people like Ferrari, so it's weird to like Alfa more than Ferrari. That argument just doesn't cut it with me.
I like the 166 more than the GT as well.
To add some specific reasons why:
1. The 166 has a glorious interior, compared to the GT/147 interior that is a bit weird - those air-vents and the centre console are just strange-looking.
2. The GT is a very well styled coupe that still retains some practicality. However, the 166 has more practicality and in addition, whether it's the pre or post facelift, it has much more of a distinctive and elegant exterior design. Yes, it's not to everyone's taste, but that's not what it's about.
3. This may not apply as much to the UK market as it does here, but in South Africa, they definitely sold many many more GTs than 166es. So in the cities, GTs are a fairly common sight, while seeing a 166 is a rare treat.