[Nexus 7 General] phonic:
Thanks, I actually work in the VoIP industry :).

The company I work for is actually very good - one of the best infrastructures around - but it's strictly for businesses that need a full fledge PBX system. Since I have free phone service through them, and have for years, I haven't looked too much at many providers recently.

Prior to working there, I used Callcentric a lot (and still have an active account as a secondary provider). They have a pretty nice platform and reasonable rates. I've recommended them in the past to people who wanted to try out learning VoIP and getting inexpensive service. However, they just suffered a MAJOR DDoS outage (lasted days) which effectively took all of their customers offline. It was their first major outage in over four years, as I don't recall anything like that ever happening before. While attacks can happen to anyone, the severity of it just goes to show how badly their infrastructure was setup behind the scenes. I imagine most VoIP providers would have suffered a similar fate if they were targeted instead, as many of them have horrible designs. Hopefully this taught them a lesson and they made drastic improvements. But as a result, I have a hard time recommending them. Time will tell if they got things right.

One new provider I was playing with recently is Flowroute. They are cheap and provide some nice features to all of their customers regardless of volume. They call themselves a "wholesale provider for retail customers" or something like that, and they certainly do offer things that many retail providers don't. They use Level3 (as most do) for termination/origination, which allows them to utilize their POPs for media traffic. However, they only have 2 registration servers, both on the West Coast. Since they don't proxy the media, this isn't too bad since the latency only affects SIP traffic (which doesn't really mean much). I haven't had a chance to test how well their "best path call routing" works, but so far the quality seems to be pretty good. However, I was not able to send faxes (ulaw) over their service, while I was with Callcentric. That is usually a good indication to test out call quality, latency, jitter, packet loss, etc., since faxes are much more finicky then humans. But you can get a free account with them and test out their service to see if it works for you.

In my case, I have my SIP client (phone and tablet) register to my home PBX, and process the calls myself. This gives me a little more flexibility to determine which carrier I want to use on a call-by-call basis, as well as keep calls to home internal.

But from a provider stand point, the pricing is usually about the same for domestic pay-per-minute or unlimited plans. If you make a lot of International calls, it's a good idea to look at rate decks to compare which provider would be best for you. Setting up a PBX using Asterisk/FreePBX/TrixBox is pretty easy and fun (for me at least), so if you are interested in VoIP, that's a good way to play around with neat things. For example, you can get a free account with SIPBroker, which has DIDs in many countries. The caller enters an access code, which can redirect right to your PBX, which you can route to your phone. So if you wanted a free way for people to call you from those countries, that would be one. I've actually used it myself when traveling internationally to call my own PBX and place outbound calls through it to the US for free.