Bat VK5i vs the Audio Research LS5 Mk1, 2 or 3...

Has anyone compared the Balanced Audio Technology (BAT) VK5i to the Audio Research LS5 MK1, 2 or even 3?
I am not interested to know comparisons with any other pre-amps just these two models in particular. Any input is greatly appreciated, let me remind the forum again only the BAT VK5i and AR LS5.