Looks like it's only available in Greater London at the moment. I would be interested in whether it introduces extra time or cost to the Fulfilment Process or whether it's really a Win/Win for small companies like us (We sell Vinyl Records) - in that they do the work and the overall costs are no more than at the moment due to their Courier buying power.
So are you willing to place a piece of vinyl in a bag that they provide until it gets to their fulfillment centre where they will repackage what is left of it for onward transport ?
As the first shipment is free, why no give it a go and send something to a friend or relative at the opposite end of the country. See how long it takes to deliver and compare it to your normal delivery method.
They may be able to offer better prices due to buying power, but this is often offset due to a slightly slower delivery time. Usually items go to their central hub, and then onward passage through the usual channels.
E-commerce , love it or hate it, that's why we are here