Thanks for your feedback David. Since we never had a chance to evaluate the ZBook 15u G2, while we acknowledge its existence, we can't really say much about how it would compare to either of these other models... so comparisons from the G3 to the G2 would also be equally impossible. The closest comparison we have testing results for are the notebooks we mentioned -- especially the Precision, which is comparable in terms of weight and size and yet manages to cram in quite a lot more power.
As we said in our verdict, we feel the 15u G3 does make sense for a particular segment of the market. It is a challenging product to unconditionally recommend, however, thanks to some other competitors in the same space offering stronger performance for marginally higher prices.
I hope this answers your question. Thanks for reading!
Steve