I use the Cardiosport Go30 which is a smallish HRM. I don't have a big wrist and find this watch quite comfortable and actually tend to wear it as my normal watch now. It has all the features you mention but I don't know about the coding. I've never had any crossover from other HRMs BUT I tend to train alone and do infrequent gym sessions.

It is pretty reliable in the pool (though won't work in salt openwater - like most others) and has a good range of features include one programable zone. To use on the bike I just strap it round the handlebar though you could probably get a mount. It has a HR recovery timer which I find useful for gauging improvement over several weeks. My only irritation is that you have to press the buttons quite hard.