Oh Dear !
Having worked for two companys recently who used NavTech I can say that I am now delighted to now be flying for a company that uses Jeppesen TAPs.
The NavTech plates try to put too much data on one plate, the east bound SID chart for LGW is cramed with so much data that the stop altitudes are confusing and very likeky to result in a level bust, it is only the fact that aircraft are usualy under radar vectors towards the end of the SID that has preventd this mistake being made.
On another STAR chart for a North African airfield the step down altitudes are unclear.
These are just two examples that spring quickly to mind.
All in all the data is badly depicted and the coverage is not the best but they are cheaper than Jeppesen..................I guess this policy is just SOP for the armed forces at the moment.