After listening to the T70, ER-4S and Tzar 350 for some time I thought the T5p had too much bass and was too dark sounding in the beginning. I was debating with myself for some time whether I could live with T5p or if they were too dark for me. So when people say headphones sound bright or dark it is alway relative to what they are used to. After some time I got accustomed to the T5p sound and I couldn't imagine selling them ever again.
I actually thought they sounded a bit thin. I was comparing them to a T1 at the time.
Like you, I will never consider selling them either.
This is a good description. The T5p sound like an improved AKG (everything is better except the soundstage).