I have been using Skype for all my calls both in the USA and U.K for over twelve months. I have reduced my telephone bill by two thirds. I spend the winters in California but my home is in the U.K. There are quality issues more generally on skype to skype. Skype to the PSTN works well.
I recently tried the new Lycos.com system but the quality to PSTN using exactly the same USB telephone as I use for Skype is very poor. Lycos is attractive because it is cheaper and you can get a U.S phone number and free voice mail . All wonderful offerings but if the basic quality is not there they are not much use.
Ahhh.. what has not been discussed are the TWO different types or uses for VoIP.
There is the home user and the business who use TWO different types of the VoIP Communications. Those being described as "Business Class" and "Consumer Class" VoIP which TOTALLY Different.
Business class would not use the "Internet" to handle IP based phone calls as of yet due to the required "Quality of Service" required to maintain a true "Voice Quality" which is in comparrison of the traditional analog circuits. Another benifit is that now the business can use "VoIP" because they are now able to pick up a phone and move thier desk from one office to another with no intervention of the local carriers. Using "General Public" voice over IP would require a LOT of bandwidth to just have a 4 line set up and running. Most business using analog service can save money on both add/move/changes AND a discount in the service costs for the analog lines by switching to a PRI (Primary Rate Interchange), T1 and up, or even a frame relay circuit.
Consumer Class VoIP is basically what has been stated here so far where the "Cell Phone" style of service is acceptable for 90% of the users. Also since it is a one to one converstation what is being established is more of a one to one bridge between the two edge devices using a public infrastructure (Internet).
All good and shiny about VoIP using services provided by certain companies.
How about VoIP "house-made" - I mean using a common broadband connection and VoIP gateways provided by hardware producers - for example, Allied Telesyn?
Or, at a greater extend, business class solutions using inhouse hardware (PCs, to be more precise) and open-source software - OpenPhone and OpenH323 GateKeeper?
If you don't buy an end-to-end solution from a VoIP services provider, rather preffer to "build" your one one, which are the options available?
I experimented once with this stuff - OpenH323 GateKeeper, and Welltech VoIP gateways and phones - and it was quite a tricky business to put it all together at business class standards.
However, it was a couple of years ago, and I assume that things are more mature nowadays.
Is it still a real option to do it your own way, or, regarding the performance/cost ratio, it doesn't worth the strugle?
You should also consider explaining PSTN failover, as implemented in modem routers such as the Billion 7404 series. It automatically switches back to pstn dial tone if either power or voip connectivity disappear.