I've been using a Garmin Montana mounted to my handlebars for some time now, and for the most part it does what I need. But it only gives me four fields on the map page and there seem to be a few possible issues with it recognising ANT+ sensors (allegedly it does but on other forums I've seen people reporting issues with it, which doesn't fill me with hope as I failed to get an ANT+ cadence sensor to work with it).

So I've been toying with the idea of looking for an all-in-one phone app, on the basis I can waterproof it with a clear plastic bag, power it for a long time with one of those external battery packs, and use bluetooth sensors if I want heart rate, cadence etc.

Any app that would make me switch to using it instead of the Montana would have to be able to do several things. I'd want to be able to prepare a route and overlay it on a map, with my position also shown on the map. I don't care about 3D mapping.

I'd want it to be able to display a number of data fields on the map (speed, grade, distance, distance to destination etc) and ideally let me choose a slightly smaller font for some fields so I could fit more in. It would be nice to have speed, average speed, grade, distance, distance to destination, cadence, heartrate and maybe a few time-related things too. It would be nice to have a few panels above the map that could be switched, or a couple of fields that would rotate through different values etc, so I could have the key information in front of me all the time with other information alternating.

I'd also want it to record GPX tracklogs so I could see details of where I had been and a few metrics along the way.

I don't know if such an app even exists, I've done some Googling and found a lot of apps with very mixed reviews. My leaning is currently towards a Windows Phone, Android isn't necessarily a problem but I'm not interested in an iPhone (my current phone is 5 years old and so a phone upgrade is possibly on the cards). Does anyone know of anything out there that does all this?