Monitoring software - update

I’m looking for monitoring software for FreePBX distro an looking for other who have done this before me.

I have found 3 software offerings that look promising.

VoIP Monitor. Looks like is has all the things I’m looking for but is cost money.

Humbug This one is missing some part, but its free for low volume systems.

HOMER 5 This is the one that looks the best.

Can anyone comment on any of them or is there something better?