Pixhawk 2.1 and Emlid, where to start?


Are thinking about start using Emlid (instead of HexAero) with Pixhawk 2.1 on a multicopter or VTOL.
Where do I start? Which one to use? RTK/PPK. Reach M+, RS+, M2 or RS+? Other?


Old Thread. Still thinking of using Emlid. Anyone tested it for RTK?