I'd resisted paying for offline maps for years, on the logic that a paper map never runs out of battery and never needs an app update at the worst possible moment. A week of patchy signal on the coast path changed my mind more thoroughly than any review I'd read beforehand.
What actually won me over
Downloaded tiles that just work with the phone in airplane mode, and a track-recording feature that doesn't drain the battery the way I expected from previous apps I'd tried and abandoned. I'd assumed GPS logging in the background would be the thing that killed the phone by lunchtime; instead I finished a six-hour day with over half the battery left.
The tile download itself is the other pleasant surprise — a whole national park downloads in a few minutes over decent wifi, and it's genuinely usable at every zoom level once it's local, not just a low-resolution fallback for when signal drops.
Where it falls short is search: finding a specific address or POI without a connection is hit and miss, and I've had to fall back on memory a couple of times for anything that wasn't already pinned before I lost signal. Worth planning waypoints in advance rather than relying on searching mid-walk.
Read more about the wider satellite messaging options if you're planning something further off-grid than a coast path with patchy 4G — offline maps solve navigation, but they don't solve being unreachable if something actually goes wrong.