Exchanging data between PHP and Flash


I’ve read that we can exchange data between PHP and Flash.
i found several ways how to do it but nothing is written regarding the best solution, or the most secured or the most easy to implement.

from PHP to Flash :
- using FLASHVARS (from EMBED and OBJECT)
- using SendAndLoad (from LoadVar) and POST (from HTML form)


from Flash to PHP:
- using object.send

Could you tell me pros and cons about them ?
is there a better way ?
thanks a lot,