I've used one of the trail apps and was satisfied, but am looking for something better. What are the features I should focus on for selecting an app? What bells and whistles are really useful on the trail?
As Rory says, low power consumption is vital, but that's likely not determined by the software, but rather by the hardware and - more importantly - how you use it.
The three key things for me in Smartphone GPS map systems are these.
- Can download maps to the device, rather than stream. (And I wouldn't trust anything claiming to just 'cache' streamed maps, because there's no guarantee that it won't randomly decide to un-cache them again)
- Can work with 'real' maps. In the UK this means Ordnance Survey or Harveys.
- Display current coordinates in grid system of your choice. e.g. OS Grid, not Lat and Long.
(This may just a long-winded way of saying 'Anything except google maps!')
But really, it depends on how you plan to use it. I travel with map, compass and brain as my primary nav. tools, and keep phone as a backup. On longer hikes it's usually switched off in an Aloksak bag, but on day hikes I may keep it running and recording my track.
FWIW, I use ViewRanger on a Motorola Defy, and I'm very pleased with both. Viewranger on iPad3 looks stunning, but you wouldn't normally want to take one with you on a hike...
In my opinion, the single best feature would be low battery consumption. You only really need a gps and map, so having a low consumption version of these would win for me, possibly with local maps rather than trying to download each section.
Battery consumption is determined by the software, too. Some stuff polls for new data, some takes GPS readings more often then others, etc.
Honestly, I do not consider using a smartphone app for hiking or getting out into the backcountry. For too many of them you need network connectivity, battery life is a real issue (compared to dedicated GPS devices), and they're fragile. I do carry a GPS but I keep it switched off unless I need it (or to mark significant spots, after which it's turned off again). Sometimes I carry a Spot, depending on what I'm doing and where I'm going.
I looked out for these things:
- Battery life: Look for additional features like Low Power Consumption mode.
- GPS Support (*Usually a common feature in all mobile phones) and accuracy with maps, with maximum support.
- Build quality: Compact, sleek and rugged design, Consider weight and frame (Metal or plastic). Should be easy to handle.
- IP Rating: For water resistant index
- Camera (Can be an optional parameter to consider, if you already have a better digital/analog camera). And inbuilt image processing quality and camera features?
My personal observation: Pictures taken on 5 Megapixel camera of Nokia are way better than those taken on 5 Megapixel camera of Motorola (Test case: Nokia X vs Moto E 2nd generation). Also, some of the mobiles have rare features like slow motion camera, which my mobile doesn't have.
- Flashlight feature? (Again, almost common in all mobile phones these days)
- Does the touchscreen have support for touch with gloves ON? My Lenovo has a mode which I can enable based on whether I am going to use it with gloves or without gloves.
- Ability to configure gestures? I can flip my cell upside down to lock it. When I bought my mobile phone, I was considering a Windows phone as well, it didn't have that feature, so I went on to purchase my existing phone (Lenovo). This is one of those features that I use a lot.