Update ( iOS 11.4.1) done on all 4 devices.
I'd be hard pressed to say that the update was 'really quick' as indicated earlier in this thread, but it hadn't yet dropped and auto downloaded yet on any ( maybe being in the 'take your time' tropics is a factor
). I did them separately one after another & was at it just over 90 min....The download - at the 'preparing update' stage was markedly slower than when in the past I'd done this before an update had dropped and presented itself -the process itself about normal. Admittedly too,my wife's iPad Air 2 and my Mini 4 while not geriatric, aren't exactly 'new kids on the block', and the phones were somewhat faster ( my 7Plus & her 8Plus) So far all appears well though. I'm figuring this is the last of iOS11 updating.
Updates OTA on home Wifi, 38Mbps Down, 16 up....