@Steve, agreed there are enough to go by. But look at the bigger picture, even more reason why we should do this locally :

 

- Can they be integrated into Asterisk or on the same server?

 

- Functionality :

 

a) Call costings

b) Departmental Call barring and management

c) Call Reports

d) Pre-paid card system and IVR balance checks

e) Post paid

 

- Costs. The last time I checked, One Seat license for proper billing/call management was nothing less than USD1000 plus annual support packages for a commercial use ( Asterisk based and also total number of extensions ) and also an issue you are looking at a 5 year support cycle for a client.

 

I also think that as long as client's have money to throw away at existing expensive solutions available and we do not provide them an option for cost effective solutions built locally, unfortunately you are right. :-)