To add my 5 penny worth...I have worn a Garmin with a heart rate monitor strap for maybe 6 years and only once did it start reading nonsense and had to buy another strap not just replace the battery. So they generally work well for me. I also have Tom Tom watch which senses the changes in the colour of your skin on your wrist to measure your heart rate....amazing but true... and I guess the 225 uses the same technology. I have found if you make sure it is tight and once you have warmed up it works pretty well but for my money not as accurate as the Chest Strap and Garmin but much more comfy!

By the way it is easy to download the data from Tom Tom watches to GRG by setting the tomtom site to automatically download to a a gpx file on your computer each time its plugged in then use the upload from gpx facility on GRG....not quite as easy as the auto upload from Garmin though :-)