Everyone will tell you that the chest straps are the most accurate.
But I am like you, I tried various different straps, changed batteries, spat on them, wet them etc. but I never found one that would work properly.
I landed up buying a polar arm band optical monitor and in 3 years have never once had a problem.
The only thing I could think is that I sweat very little so even if I wet the thing, me and the strap would be bone dry with in a few minutes. Especially in winter.
