Acustic vario VS gen3
The acustic vario is better.... i will compare next week with gen4 ... this is my video: http://www.vimeo.com/13826887
Yes acoustic vario(I think is the Last one down from trappy) should be better than G3 GPS based vario.
But G4 Vario is also barometric, it use a 16bit ADC converter and outputs vario output by using a very low time delay filtering. So I think it should work equal or better than acoustic vario. Of course, ones in the air all this is very subjective. Because there is not a third independent absolute reference.