Never heard the system in a 430 or 460, but the 400 does sound pretty good, mainly that you can hear good quality (not just quantity) bass while on the move, which is not so easy to achieve.
I found it odd in the review that one fault was the placement of the CD caddy. I personally would have zero intention of fiddling with 6 CD's while on the move, but maybe with USA roads being wider, you can weave about a fair bit before hitting anything.