If you need the box now buy it as prices will go up due to weakening pound.
If you don't need it, wait for more release of 4K boxes and prices will drop, perhaps not to the levels of non arm boxes.
Not bought a 4K as no need, there is no content and when it does arrive unlikely due to encryption will play on non provider boxes at least in UK and Western Europe.
Sent from my SM-N9005 using Tapatalk