The Zepp Golf Analyzer is an inexpensive low power Bluetooth device that attaches to your golf glove and provides analysis and statistics on your golf swing. From a power perspective, a single charge provides for monitoring a typical 18 round of golf. Hopefully, in the long-run, a single fitness sensors will be able to monitor multiple sports. How many single purpose wearable devices can you have without absolutely going crazy?
In any case, Engadget, claims this to be the best golf monitor currently on the market (about $119 on Amazon).