Positive:
Accurate to 1 yard.
No need to download courses like on a gps unit.
Ready to go anywhere.
Once purchased only needs the occasional battery.
One push of the button and you have 8 secs to check the distances to hazards, flag etc.

Negative:
Will only measure to visible targets.
Doesn't work well in rain or gloomy conditions.

Overall:
In my opinion, miles better than the gps units currently on offer.