i have not seen the ones you mention, i got the Peripheral PXDP iPod2Car interface for iPod (
http://www.discountcarstereo.com/detail.aspx?ID=360)about a year ago. comes with a long cable so you can put the ipod anywhere, and you can use the stock stereo controls with the ipod. very easy to install. i love it, so much better than the many fm adaptors i tried. let us know what you get!