"a mí casi no me gusta"
 

I know this is a less blunt way of saying a mí no me gusta, but as far as I can tell, I only hear Colombians using it. In your experience, have you heard others using it?

The phrase gets lots of hits on the Internet, and I don't think they all came from Colombians. I've heard it used outside of Colombia.

"Casi" is a very handy nuance word. :D

It depends on the situation and how prone individuals are to euphemisms, but I definitely don't think it's only Colombian. :)

When I read it I thought it was a female speaking
Here in Spain females use that "casi" (really meaning "nada")
"a mí casi no me gusta" --> real; a mí no me gusta nada
"va a ser casi como que no" --> real: "va a ser que no seguro"
It's like the often heared:
"¡Yo estoy bien aquí, pero si quieres nos vamos!" --> meaning "No me gusta nada estar aquí"

Saludos :D