I'd like to hear why you think the change rots, as well as hear from others with recent US Airways Shuttle experience.
I fly the Delta Shuttle all the time but have only used US's offering a couple of times. I've noticed that the US Airways Shuttle now uses E190s between Boston and LaGuardia, and that is an aircraft type that I generally tend to like. The US Shuttle is sometimes more convenient for me than Delta, so I'd definitely be curious to hear about experiences with the product.
Also, besides the 500mi minimum and no advance seat assignments, is the Shuttle experience any different than mainline nowadays?
BOS2DCA: The BOS-LGA Shuttle is now operated by E190s. I think US is now dedicating the fleet to BOS-LGA/PHL (previously I think they flew pretty broadly, but typically PHL to Northeast points). I quite like the E190. No middle seats, giant windows, full-size cabin and overhead bins (though rollerboards don't fit in lengthwise like in bigger jets), and FC cabin with single seats on one side.