This is key, color changing GI is cosmetic but color changing inserts give the programmer flexibility to make varied and interesting use of the available shots. Of course color changing inserts are not a bash toy or drops (especially to the casual player that's more likely to be drawn in by visible stuff on the playfield), and they may just be a given for any new pin at this point, but still a noteworthy upgrade compared to IM.

What happened to sound on the IM Vault? Cheaper speakers?

Sorry, I misread and thought you were talking about IM Vault sound (which is identical, I think), not SM Vault sound (which as you say was totally redone when they reskinned the game). Oops!

Seems logical Stern just found their own supplier in China to make "Stern" LEDs for them. Everyone's sourcing from China anyway, and Stern's clearly the biggest single LED customer in pinball. Also, Stern wouldn't benefit in the same way as an end-user from the customer service and array of stock that Cointaker, Nifty, Comet, etc. can offer.