* Even when it warns that a cart is low, you keep printing. There's probably a dozen or more 16x20's left in the cart. You can change carts mid-print without affecting the print, so you just keep going until it asks for a new cart.
* Changing a cart does not touch the ink levels in the other carts. Only the changed line is primed. Most ink jets prime every line once a single cart is changed which defeats the whole purpose of individual carts and is a big part of the reason why ink disappears into a void.
The only drawback is that the glossy and matte blacks share a line, so if you change paper types you lose some ink (a few bucks worth). So you need to batch your prints by type. But the printer performs so well...and the carts last so long...that this is hardly worth complaining about.
I have a feeling that the Pro-10 doesn't have "hot swappable" ink tanks.
I have also been wondering if all inks are primed when one tank is replaced. I haven't been able to find any support in the manual yet.
Is there an Epson that shares the strong points outlined in your posting but doesn't require a change of black ink for glossy/matte?