Pros It, uhh, stands up on it's own?
Cons $30 for what is essentially a USB extension cable with a plastic stand built around it. You have got to be kidding me. $5, sure. $10 maybe. I think I'll just use my usb hub, or one of the spare ports in the front of my PC instead.
Pros This is just a cable extension (unlike the regular iPod docks, which also have a line out), do it's only useful for convenience. That said, it looks good and is certainly useful if your USB port is difficult to get to.
Cons Should have had a line out port, like the other iPod docks. Also, if your USB port is readily accessible (e.g. on the side of a notebook), then you don't need this. Otherwise, it does what it says.
Pros Looks pretty.
Cons It's a cable. No con.