UKC

I had OS Maps, I let it expire as it's cheaper to repurchase with the 30% discount you get with different clubs than auto renew. I get a free account as a D of E leader too, so I still have access for browsing / printing, etc but I don't want to confuse things with my personal use. It does give me the time to consider what the alternatives are nowadays.

Compared to OS Maps (which I'm happy with) what extra features might be good from Hiiker or one of the others. I will navigate from the app on holidays in places where a paper map isn't needed (maybe a bike ride around where we're staying or a short easily marked route), otherwise I buy paper anyway.

I mainly use it for pre-trip planning. I record my trips in Garmin and that pushes to Komoot. When I plan bike routes I do it in Komoot and the import to OS to check out the terrain.

You'll likely get the option for the Harveys maps on some of the alternatives. Its one thing that's missing from memory map.

Osmand is worth getting. It's a free OpenStreet Map app, you get a number of free downloads of detailed maps to use offline (at some point need to start paying for new areas). Very good coverage of paths, etc. I've found it excellent for walking on holidays outside UK. (A downside is it doesn't have vertical topographic features like contour lines you would get from a good walking map so not the best for real mountain environments, though I think these can be downloaded as layers.)

1. OpenStreetMaps occasionally have problems in mountain areas, bad elevation data inherited from old DEMs (depends on the area and data source, though).

2. OsmAnd is nice, but the absolutely needed paid functions (contours) are rather costly. Mapy.cz used to be a much better OpenStreetMap app (allowing you to download the whole world offline for free, including contours and slope angles),  but they went paid premium for unlimited downloads as well.

3. Until Ordnance Survey "someday" (i.e. when pigs will fly) releases the 1:25k maps under an open licence (as other equivalent agencies did years ago, all their work being tax‑payer funded after all), your only option of accessing them through another app would be likely to pay for them again through that other app subscription or payment (Outdoors Active, which underwent strong enshittification recently, or Locus, only for Android). Might be a few others there I missed.

I am on Outdoor Active. I have full OS of the country in 1:50k and 1:25k, I have Harvey's on there too and if I was going abroad I could subscribe to other countries outdoor maps on there too. I have found it not too bad to use and I like having the variety of maps. 

MemoryMap have their sale just before the end of the year, so you have just missed it.

Personally I went for a perpetual licence with them, rather than yearly, as long term it works out much cheaper. Then downloaded the whole of the UK onto my phone so it’s always available offline. MemoryMap gives you the ability to share the licence across several devices.

However doing that means you don’t get updates……with occasional ‘who put a wind farm on my Corbett’ moment.

As to features cannae help. In case you are not aware you can get a French IGN for free via their own app.

And SwissTopo, and Norgeskart... lots of mapping agencies are making their data increasingly available. 

Is that with Pro or Pro+ ?

I was only considering paid options that give me OS maps- essentially giving me same functions as OS maps or better.

Seems to be Pro+, but I don't remember what that gave you extra to Pro. I have had it for ages so don't really remember what options were available 

Have a look at Topo GPS. It was recommended on here by someone a while ago and I’ve found it the closest thing to the sadly missed Viewranger. You have the option to buy mapping ‘by the tile’ or by subscription, you can add points of interest (sadly not available on OS Maps), and you can print OS maps to scale at A4.

With Locus the OSM maps display contours when you go to more detailed views.

OsmAnd is free, even with those features. It's GPL. https://github.com/osmandapp/Osmand 

They keep it fairly quiet but you'll only pay if you install it from the app store. Easiest way to get it is via FDroid. https://f-droid.org/packages/net.osmand.plus/  if you don't fancy building it yourself.

Ideal for this, and not mentioned yet are:
Alpinequest - it's ok. Not great not terrible.
Oruxmaps - marmite UI but if you can figure it out it's good.
Organic Maps - probably the easiest to get on with. Simple, basic, just works. Super easy to download areas for offline use.

If you absolutely must have OS maps, then I think I know a guy who might have some ancient perl from the turn of the century that could help....

I quite like Anquet as an OS Maps vehicle. I'm nt really sure how it compares with the other apps.

Another vote for Organic Maps. Really easy to use

🤣 I had forgotten about that.

Not only that, but you also have total control over what level of detail is shown at what zoom level, how each item is rendered (colour, weight...) via a bit of XML and OpenAndroMaps. If you're inclined to that level of nerdism. It's worth remembering that OpenStreetMaps, despite the name is not actually a 'map', it's just a database of geographical features. There are then various 'backends' that interpret that data and draw the actual vector or bitmap maps and then various apps that can display those maps on particular devices with different degrees of control of how the raw data is rendered. It's complex but powerful.