Hi, I didn't compare the VK60s to the VT100, but I did compare it to its big brother the VT200. The mono VK60s were more open and transparent giving images a uncanny sense of presence. The only area where the VT200 beat the 60s was in bottom end tautness and overall volume levels. I wanted to like the VT200 more because it was a little less money and more power. But to my ears the VK60s blew away the VT200. The ARC sounded grainy in the midrange compared to the BATs, this was very apparent on vocals, females in particular. The sound stage grew in every dimension with the BATs, a tell tale sign of true resolution because that low level information is on the source. The VK60s have the magic of a single-ended amp with the power and control of a push-pull amp. Even in the bottom end the instruments had more space and timbre giving a more realistic sonic view into the bottom octaves. The tightness in the bass depends on how low the impedance dips on your speakers in the low end. This is due to the fact the the Bats are not a push-pull design and have no negative feed-back. On the right speaker the bass of the 60s is very tight buy tube standards. The beauty of the 60s is that down the road if you want more power you can always go to 4 of them, this doubles the power and cuts the output impedance of the amp in half which gives much better control and grip over the speakers. Plus you double the energy storage to a whopping! 1800 joules of energy storage for those demanding musical peaks. Please keep in mind this is only my opinion and please trust your own ears, but to my ears the VK60s are in a whole different league than the ARC. They are startling in their naturalness and have the "MAGIC"