Baranyi,
The Berning is all that & more. It is definitely better with a preamp, but still better than most other things running direct. Buying the Berning now, and waiting on a preamp might be the ticket for you.
I didn't have the Berning until a few months ago, and the VR4.5s were sold long before, so never heard them together.
This amp is so far in a different class than the others mentioned in this thread(as it should for the price), it's like comparing a Ferrari to a bunch of Hondas & Toyotas. They might be overachievers at their price point, but head-to-head, no contest.
RE: BAT cables, you don't need twice as many cables, you just need interconnects with XLR connectors. Your speaker cables can still be single wired or bi-wired, your choice. I used a few different ones: Transparent, Audioquest, Audio Magic(who makes the VR jumpers).
Cheers, Spencer