To make things a little more tangible I did a ride in the car. I installed osmtracker (from the f-droid repository) on Fairphones and one Galaxy SII http://www.mygpsfiles.com/app/#DgLGaXXF
- Amsterdam average elevation is 2m so the ~60m of the S2 seem quite off.
- On http://www.gpsvisualizer.com/elevation you can upload any gps track and view the SRTM elevation profile corresponding to the stored coordinates. The values are around 0-5 meters and not around 60.
- I used the gpsvisualizer site to replace the coordinates in the galaxy s ii track with the correct srtm elevation values and added this to another gps view: http://www.mygpsfiles.com/app/#LemYkE5y
In summary the fairphone gps elevation looks quite good (keeping in mind that the vertical accuracy of gps will always be worse than the horizontal).