In reply to womblingfree:
I find the OS map perfectly usable for navigation, although I'm not a big recorder of routes. I much prefer the clean display and lack of cruft to Viewranger, which I haven't used since getting the OS app. Development appears to be ongoing - the 3d display they added to the web app last week is very good.
Worth noting that if you can pay with Tesco clubcard points annual OS sub is only £8.