...
I've tried Jitsi, but can never seem to get anyone to use it, so... pretty useless.
...
-Renegade
I too tried
Jitsi, also
Linphone,
Ekiga,
Twinkle, and a few other obscure SIP clients. The trouble is, it seems like every
SIP network has their own client, none of them work together (actually, that may have changed in recent years), and they all charge money for calling land lines. I have accounts with
IPtel and
Ekiga, though I haven't logged in for so long, the accounts are either lapsed or I've probably forgotten my passwords, and they were probably linked to my Lavabit email, so recovering is an impossibility.
So much easier to use Google Talk from Gmail.com, which is free to call land lines in the states, so if I ever need VOIP, it's either that or
Mumble, which I use to talk to my son when he's out with friends and needs me to troubleshoot the Minecraft server.
I also kept hearing that while SIP works pretty good for voice alone, it sucks when trying to shoehorn video in with it, so there were several proposals to 'upgrade' SIP to something that can handle realtime video calls and teleconferencing. Skype was really happening around the same time, so nobody cared and nothing was done, IIRC.