TBM, you are not going to get any better right now and at least this one is using the right engineering.

It will use a little battery even when not on screen(they call it background mode) as it "bleats" a small code which all the others can catch up and note. Not significant in reality unless you were to spend a lot of time in a supermarket where they are all bleating and listening. Even then quite low.

My impression so far is that it seems design-by-committee but capable. Why open the app and then have to press a button to go into QR scan mode when that is the 99.9% use it will get. You should just open the app and it goes directly to scan with a small menu bar for the other stuff on the bottom. Waste of time and typical lazy UX.

I am using it now. If you want to register your location so that people can swipe in/out then simply go here - https://www.gov.uk/create-coronavirus-qr-poster
We have it for our office so that the posties/staff and a very few visitors can locate.

Everyone loves a Morgan. Even me, unless it's broken again.