I have a POTS line plus have been using various VOIP services for past 3 years.

I am based in Canada and have 7MB DSL service (actually receive about 5MB) and 800 K down (receive about 600 K down).

The ISP is traffic shaping.

I have used 5 services thus far

Broadvoice - using Michigan number, very poor call quality all the time @ almost $30/month(used both softphone and ATA)

Acanac - local number, poor voice quality (softphone & ATA)

Skype - no Skype in number, use apps on Windows XP dual core laptop and UMPC (HTC Shift) - sometime has good call quality, sometimes not, on UMPC, I think Skype takes too much processing power, calls 90% of time are poor

Gizmo5 - tried to today, does not allways connect

Jajah - works well most of time, some calls have poor quality, use it with HTC Diamond soemtimes as incoming call are free on mobile except in USA.

I have a Linksys high end router that Skype works fine and have been able to make calls out on Gizmo5.

My questions are as follows:

Are all VOIP services the same voice quality (exception being cable based ISP that offer VOIP service on their private networks)

Is there a benefit to having a provider that works with ATA vs software only solutions (I have wireless headset and really do not need ATA since headset connects via USB/POTS service and Wireless phone)

If my ISP is shaping P2P traffic, would this be causing issues with Skype, sometimes friends and family can not tell I am calling via internet, sometimes others have issues hearing me when I call them, I hear them perfectly. My concern is for business related calls, not personal.

Are their softphones/services that have less overhead that Skype that work in Canada.

If I have Exchange client(connected via RPC over HTTPS) open at same time, would this be causing issues with Skype call quality?

I really would like to find a inexpensive service (Skype seem to be good price) that has a low overhead client and excellent call quality.

Based on reading, Skype seem to use excellent codecs for networks that may have latency (ie 3G service)?

I would appreciate some assistance.