I may one of these days. I don't actually hate Premiere, I've never had any deal-breaking issues with it. FCP just came with such a good suite of applications that worked very well together.
The only reason I haven't really tried Vegas is that, to my knowledge, it doesn't work with YUV color, while Premiere has no issue with it. I prefer to keep the colorspace the same through the entire workflow.
Of course, this is a topic for another thread, so I'll leave it at that.