I like the SC430 because it's pretty unique in the market....as Ron said, not-sporty at all, but focused luxury with the retractable hardtop. Really nice driving cars, if you like a soft quite ride and don't expect a sports car. I agree that they look a little bloaty and awkward though.
Seems there are two options on the market; either dirt cheap and totally clapped out high mileage units, or very well kept 'weekend driver' type examples that are still commanding pretty good money.
A neighbor of my parents had an SC4320 and an 07 Jag XK, when the owner died the widow was looking to get rid of both of them. I did buy the XK, fixed up a few needs, and sent it on. Had intention to buy the SC430, and had aligned on a price, but she ran into issues getting the ownership from the estate and the deal sorta fell off. I think her daughter ended up driving it for awhile, not sure what eventually happened to it. It needed brakes pretty bad and the undercarriage was getting a little crusty.