I don't know which is worse.......the US Mail or the Royal Mail. Mailers Beware!!! If you need to send something overseas that is of any importance at all, send it either by UPS,FED X or even DHL.
A friend of mine has sent me something twice from the UK and twice it's gotten lost. The more I hear from other people over there sending items to the US, the more I hear about packages getting lost and never showing up again. I lost a lot of faith in the US mail awhile ago, I think I have finally lost all faith in all of the US Mail and the Royal Post (or whatever it's called).
Just be cautious when sending items of any value. Make sure you take out insurance if you do use the regular mail.