I've tried every IAX softphone I could find. (I'm looking for one for our
office users.) I came down to three:
Firefly. Liked it a lot. But eventually, I decided it is not a good choice
because it doesn't appear to be supported, or updated.
DIAX. Like it. Many, many features. But I decided the interface is too
unprofessional for business use. Also, appears to be a single person project
- software hasn't been updated in a while.
IdeFisk. Initially did not like the interface. But they update it frequently
and are very anxious to get feedback and implement changes. (In fact they
just released v1.32 yesterday that is a great improvement over v1.31) They
will support it, if you purchase the pro version. This is the softphone I am
recommending.
If I was just using something at home, for myself, any of the above three
would be a good choice.
Mike