You have me intrigued ! what's the difference other than game fishing equipment has a cost premium and more snobbery factor ? ? 
If they are tough and don't bloody leak every few months then i really wouldn't care if they don't have all the 'bells and whistles'
They are heavy weight, with big pads stuck on the knees/upper shins, making them uncomfortable to walk in. The cut is a bit crude as well, with a simple round top with draw string. The gravel guard is neoprene, so quite tight (to stop sand on the beach). The bright yellow 3" wide belt is a bit in your face too. They only come in a small range of sizes so getting a good fit if you are of a challenging shape would be a real issue.
However, they are designed for clambering over rocks and barnacles, as well as keeping you warm and dry, so if you can live the more "industrial" look and feel, I can imagine they would last well on a river. The built in knee pads would be worth their weight in gold on the Don.
Cost wise they come in at £270.
As I say, Vass has its origins in industrial wear, so tend to make pretty robust stuff, but it is never pretty or comfortable.
