More than half imo, my Forerunner 265S is pretty much a full-blown coach that fits on my wrist. It adapts training to my sleep (such a great feature when you've just had a baby) keeps track of load, low aerobic, high aerobic, etc...

It's been a fragile piece of hardware, I am on my 3rd one in as many years (always replaced under warranty though), but I still probably wouldn't switch to anything else. When it breaks out of warranty I'll just buy another one.