I love my Virus but the VC arp is simply unbearable.
So, I decided to run a test.
I took a snapshot of the Virus' MIDI output (Yellow) along side a MIDI Arp VST (Orange) to see the difference in Timing.
These are not Quantized so you can see the difference in what is actually being spit out.
It's actually embarrassing for this to be this bad.
This is the result :
[Blockierte Grafik: http://img607.imageshack.us/img607/9907/miditest2.png]
You can clearly see a slant and notes that are out of sync where as the VST on the bottom has perfect timing.
Sad is that I'm playing 1 sound with NO FX.
Yes, I tried different latency settings, outputs etc... but the Fact is,
We shouldn't have to jump through work arounds to get something so basic working.
IMO The ARP should be forced through the MIDI out because it's obvious the USB can't handle the throughput.
Someone f'd up big time in the developement stage here. This MUST be fixed along with the arp falling out of sync....
Oh, and let's not forget that the Arp out only works on odd midi channels!!! ... What is that? 
Please, Do us a favor, Stop adding all this other stuff and let's get the basics Working so we can just Plug N' Play!! 