These images show the differences:
Here's the Britkits cab view:

and here's the VRR equivalent:

No, they don't show the cab from the same viewpoint, but the differences are obvious nonetheless. Why does this matter to me? In the first place, because while I do not always drive from the cab, when I do I prefer a detailed view. Secondly, because when I include an engine in one of my scenarios, I prefer to provide those who will drive that scenario with a detailed cab view. The VirtualRailroads RS-11 pack costs 10,88€ (without VAT): $12.15 at today's rate. I don't favor making others buy payware in order to run my scenarios, but I will probably begin to offer alternate versions of my VNHRR scenarios that include the RS-11 which require the VRR model.
Now, if I could only find an equally detailed model of the Rs-3!
Again, just for comparison, here's an exterior view of the two models:

Interestingly enough, the Britkits model drives short-nose front, while the VRR model is the opposite.