Versatrak AWD handling

I've been trying to find information regarding how the Versatrak AWD system is performing, most importantly in winter driving conditions on slipery roads. I find very mixed opinions, from that it performs well to that it engages the rear wheels too late which can cause unpredicable behaviour.

I therefore ask here if anybody have first hand experience of the above and can share their opinions. How does it compare to other part time awd systems?