^^ I have that knob and I absolutely love it, for a number of reasons (see also my post #24):
(1) It feels better and more solid.
(2) The way it interfaces with the boot looks SO much better than the SVT one (no "pencil neck"). I don't have an STS, but with the ST220 knob it almost looks like I do.
(3) It looks badass.
Now, with regard to your questions:
(1) I have the blue seats, and my overall interior looks way better with that knob.
(2) The color of the knob definitely doesn't match the color of the e-brake button. The knob looks almost like smoked chrome, while the button is, of course, matte silver. This doesn't bother me at all (but, then again, I'm waiting to install my Richbrook e-brake handle - with a big honkin' chrome button that actually MIGHT bother me - so I'm not concerned with the SVT handle).
But here's a biggie: I'm actually thinking that handle in the pics above may or may not look a bit out of place; I'm not sure it goes that well with the standard charcoal/black/drab SVT interior (maybe it does, I dunno). You see, my interior is slightly blinged out with CD Silver interior painting and billet knobs:
It may or may not be your cup of tea, but that's not the point; the point is: with MY interior the ST220 knob looks AMAZING.
I haven't taken any pics yet because I've been waiting to finish my two other console projects first....