No sir, I don’t like it.
I don’t find it adds anything. I’m perfectly able to read across the lines of a plain old static table, so highlight one line doesn’t make it any faster to read that line. It also doesn’t help me pick out a line when scanning with the mouse, because I’m already looking at the line that gets highlighted – I put the mouse there myself!
I don’t know if it’s just my browser, but highlighting the line causes a lot of flicker. (The “more extreme” example from Neil Roberts is even worse – it actually resizes things while I’m mousing over them, jerkily. That’s terrible!) So I’d really hesitate to use this until it’s been tested on a lot of browsers and setups to make sure it’s smooth everywhere.
The only advantage I could see is if I look away and come back later. There might be some value in highlighting the line after the mouse has stopped there for a few seconds, which wouldn’t cause flicker when scanning quickly. It still might be more annoying than useful, though.