[SR-Users] keep buddy list - best way

Hello Sirs, I'm a little confused getting a decision about implementing buddy list (step: presence & IM). What is the best way for keeping the contacts list: xmpp or xcap? You will say probably xcap server but even if I intend to use in the future an xmpp gateway in order to be able to communicate sip with with xmpp servers like google - google talk? And why xcap? Because most of the clients has the possibility to connect to a xcap server to get the buddy list? From web perspective I think both are OK because of the xhttp module power in kamailio to get the buddy list xml. Thank you. Best regards, Mihai M