Only disappointed in the IECC one time, the first time I got glasses and they didn't fit them to my face. I didn't know any better since it was my first pair so I didn't say anything back then. The next pair they fitted when I got them and what a difference: that pair is so much more comfortable and stays in place.
Other than that I have never had a bad experience at IECC. Doctors are always pleasant and take time to check properly.