a training can be recommended. There are a lot of enhancements to look at and to understand. Without it it hard to find the way -> only with help and command finder is a poor solution
NX6 is a lot easier to use, once you familiarize yourself with the layout changes. It will take a little effort to become comfortable with the changes, but once you do you will really be glad you upgraded, as potrero states.
"Good to know you got shoes to wear when you find the floor." - [small]Robert Hunter[/small]
NX-6 is not wholly unlike NX-3 despite some apparent visual cues to the contrary. I think you'll find it a lot slicker with features you'd have wished for in earlier versions. Personally I think you'd have found it easier to go from NX-3 to NX-5, but it's too late for that now. Don't leave it until NX-7 I think you'll find it more of a stretch if you do.
There is a little bit of new functionality with direct modelling being re-badged to synchronous modelling and all that, but I think you'll find most of it still correlates. There is also some other new functionality, but the old tools are also still around when you need them so you will for the most part be able to ease yourself into the process of weaning away from the old towards the new in a fairly painless way.