For me, i am not sure i want this.
#1. you need to pay more to your carrier to have a cellular watch (usually $5/mo extra) for a function that is rarely needed for most folks.
#2. the speaker now is pathetic, esp outside with ambient noise...how can you even hear the other caller?
#3. because of #2, you will have to invest in bluetooth headset (Beats and Airpods).
#4. battery life would be drained rather quickly and that may mean that your jog or bike ride may have to be cut short because you're chatting with your wife with the watch while using GPS to track your activity.
#5. because of #4, you need bigger battery and maybe even thicker watch (see LG Sport that just came out!)...my wrist is small enough...i don't need Watch to get bigger!