My $279 delivered[cheap in Oz] N.I. KA 6 Interface is even MORE tank like,it's heavy!
And runs crazy lower latency[guitar sims anyone?] than the VS-100,like 32 samples,with plugin heavy tracks,when the VS/Sonar will NOT even open a project,untill up around 96[at the VERY least].
I think I might resell mine[if anyone will buy it]This:
http://www.oblique-audio.com/ is an excellent tool for measuring TRUE Round Trip Latency,as all DAWS,Interfaces are slightly optimistic,in their readings,all of them!
The VS-100's USB 2.0 RTLatency is not good,but if you don't mind 12+ms Round Trip,at the VERY least,or SONAR will NOT open,let alone play cleanly,but when it does[188 samples!!],it's got better preamps,and possibly conversion than the KA 6,but so it should!
I think the main problem,is it was released when USB 2.0 was still kind of new,but even with a crazy cheap $162.50[AUD] pricetag,I'm dissapointed,with the 2008 RTLatency,even though it was made in late 2009.