Is Prepar3D version 3 better ?

Definitely.   I find improvements a little bit here, a little bit there.   Overall about 10% better than the last version 2.5 in general I would say.

Justified to pay in full again ?

Definitely NOT.   I accept an upgrade fee but definitely not willing to pay in full again.

Sadly, we don’t have a choice if we want to stick with Prepar3D.   We will do it sooner or later eventually.

Finally, be prepared to pay again after another 24 months or so.   What a company !