I was talking to shinobimonkey about this, he's been doing it for 12 months now.

He uses Samsung edge 6. Initial synchronization took him about a week with him leaving it on charger as much as possible. He sync'd at around block height 450000 (so about January 2017), and both blocksonly and pruning are enabled. He says he used a version of bitcoin core 0.14 or thereabouts. The ABCore GUI has an option to only allow sync'ing when on wifi and charging.

I'm actually impressed how near-possible it is to be running a practical smartphone full node today.

Smartphone full nodes will be important going ahead because smartphone usage has already outpaced desktop for some use cases (e.g. web browsing) and is only going up from here.