As a person who's done hardcore HRM training, I think that the rants against wrist-based HRM are over-hyped.
Yes, it's less accurate than a chest strap, but it works fine for 99.999% of what pretty much anyone wants to do with it. Assuming you don't have mutant wrists, for best results, make sure the strap in snug, but not too snug, against your wrist.
And wrist-based HRM has improved quite a bit in recent years.
