To me, depends on precision you require, if you do not precision of more than 10-30 meters between one point and another you can you your smart phone with a GPS application, otherwise if you need more than that you will need a professional GPS with more accuracy. From 2015 a new technology of GPS is coming, more accurate, so if its not urgent and so accurate, smart phone, if not, wait for 2015.

I use gps supporting raster graphics. You can use any map with these devises, also possible to use smartphone with raster maps