These were fitted to my Djet by a previous owner. My priorities are: wet braking, wet lateral grip (slick roads, not deep puddles) & progressive & talkative behaviour on the limit. I have no interest in comfort or longevity & prefer to have a short life, wet road friendly, soft compound tyre. Wet braking was ok but I considered them appallingly poor on most of my priorities. Instant plough understeer that was difficult to tune out with tyre pressures (I ended up with 39 psi fronts & 31 psi rears on a mid-engined vehicle!) & general unresponsiveness to inputs (initial & corrective) & low wet grip levels were notable. Shifting to my current Continental PremiumContact2s transformed the car's behaviour on each of my priorities.
The 155/80-15 size is an awkward one for anything decent in tyres & were I to be motivated to return to 15" wheels, then the FF soft compound version of Michelin's Xas seems likely to be a better proposition (I found the regular Xas rather good in the wet & very taut in structure when used on past vehicles).
So: I don't recommend the Vredestein unless pootling about on dry roads is all you'll do.