I have owned the VAC Sigma 160i with built in MC phono stage for about 2 years and continue to be impressed with its sound and build quality as well as the support of Kevin Hayes and company at VAC.
I find it to have a beguiling combination of the liquidity and dimensionality people like from tubes along with the resolution, drive and bass control that people typically associate with good solid state.
For me it is the cornerstone of a high quality, but simplified system and I would highly recommend an audition for anyone in the market for a great integrated at that price point.
I have not heard the Accuphase but I have heard the Luxman Class As, Pass Class A, older ARC Vsi50, various Mcintosh, older Ayre and many others, and still preferred the VAC by a pretty good margin for my tastes (classical, jazz, blues, acoustic, some rock, etc).
The new Ayre 5 series integrated has a nice sound as well and the Vitus at a higher price point is also a good sounding integrated that would be worth consideration.