I didn't care for the Tf-10 but didn't find them sibilant. They do have extended and pronounced highs but it's rather peak free. My take is that they just lacked too much mids for my tastes and the bass was more mid bass prominent. It's not a bad phone and there's a reason many really like it. The mid bass doesn't bleed up for instance like on many such phones so if you like a v response, it's a good choice, especially for what you can now get them for.
That's similar to my take on them. I can see people like it but it's not for me especially the fit.