Strengths: Combines ave pace, elapsed time and Heart Rate in one display. You can combine a number of other pieces of information as well. Easy to set up and putting it all on is no problem. Very simple to use.
I find it especially useful to monitor what I am doing on training runs - whether that is to keep heart rate down so as to run further or to get pace up on a speed session this piece of kit gives you an objective view.
Weaknesses: Mine just eats batteries. I have high powered rechargeables - even when they were new I was getting less than 12 hours out of them. Not a problem running, but means having to take spare batteries when I go for long walks.
Doesn't show elevation, but I think the latest trailrunner model has this feature.
My HRM packed up very soon after I bought it, but Timex repaired it very quickly.
Overall: Glad I bought this. It seemed extravagant at the time, but I wouldn't be without it now.