Theoretical performance hit via Voxalot
 

I am new to this service and found it amazingly useful, at least when registering my SMCWTVG to Voxalot it always gives good dial tone when otherwise it's hit and miss when using other direct VSP (we won't dwelve into the why's here, I think this is a bug in the device, the Linksys ATA don't have such problem), so I am going to start using Voxalot exclusively for this device.
I have a question as to whether there should be a performance degradation, even if it's entirely therectical, when going via a 3rd party registration such as Voxalot? May be an additional packet delay? Also what appens to the STUN server configured on the device, does it still provide a straight voice stream between the two connecting devices? (thereby negating any real performance degradation)

For the most part VoXaLot only involves itself in the handshaking / signaling part of a call. If the device configure to handle NAT (ie using STUN or port forwarding techniques etc) then the RTP voice stream will be point to point and bypasses our proxies.

VoXaLot is also setup to perform RTP proxying when it detects the need to.

Hope this addresses your question?

No in my opinion there should be no additional delay whatsoever if you are using STUN. A working STUN configuration on your SIP device would open up all the SIP and RTP ports needed for calling to work.

Voxalot, when using a 3rd party provider, only works at the level of SIP signaling, to negotiate call setup and tear-down. The actual UDP stream of voice packets is setup directly between your IP and the destination IP of your provider, with no unnecessary middle-man introducing latency. At least that holds true when STUN is being correctly used. Voxalot acts as an outbound proxy (and a middleman) in the event that STUN is not working, which does increase latency, but the alternative is the call would not even work at all otherwise.

Many thanks for the advises, I thought as such but it does help to get clarification from the experts. In this case there is every advantage in using Voxalot, I find that registration at Voxalot is very easy and seems to be more reliable than any other VSP (whether it is true or not, this is my perception)