I use Safari 4 beta on My MacBook Pro, it looks very clean, scrolling is perfect, and super fast. For secondary browsers i use stainless,opera,firefox in that order.
On my work machine/and windows pc i use Google Chrome as a primary browser, with Safari 4 as secondary.
iPhone, mobile safari of course, as the main browser, and i use another browser called "aquari" for a secondary, its amuseing to use just for the heck of it. Its as we know just safari with another skin!