SPS is definitely the "safest" in the sense that it's precise, but it does have issues occasionally. Your other options are:
- ObjDTM walking: I haven't used this, but it seems to work very well. It's very precise. Check out
euphemism's tutorial for this.
- DTM walking: Very good, but can be hard to make a working DTM path for some areas. It is also very susceptible to color changes. Check out
DemiseScythe's tutorial for this.
- RadialWalking: Fairly reliable. Your whole walk path could be messed up by a single click, so I wouldn't consider it "safe".