Getting featured is the ultimate goal of any developer because it instantly means lots of exposure and therefore sales. Unfortunately, it's generally only the big name software houses with already famous titles that get featured but then Apple does warn developers to have some high quality artwork ready in case they ask for it to be featured. Don't blow the opportunity if it ever does arise!!
Of course, a TV ad feature is the ultimate holy grail for any app, but then you may have a better chance of winning the lottery
Actually, I think the top What's New spot on the phone is worth much more than the tv commercials, as you're constantly visible for a least a week or two on millions of phones. I've been in the top What's New spot before. I'll let you know how it compares when I get a commercial.
Basically, bottom line, don't count on being featured. If you do it's a big bonus. Note the What's New section is actually called "New & Noteworthy". What's noteworthy? Only Apple knows!
I'd say getting one of the top premium boxes at the top is really good for your app but I don't know yet