How long do uncut, fresh strawberries last in the refrigerator?
It's very variable. I've had them last well over a week especially the best of the small ones I grow (if they're a little overripe they get eaten immediately, if slightly damaged they get frozen to make jam when I have enough). On the other hand one soft one in the bottom of the pack can reduce it to a couple of days, and this can be due to damage in packing or transit. If you spot the soft ones straight away you can still eat them and the rest will keep, but left too long they'll go mouldy. 

I haven't noticed a difference between the keeping properties of organic or cheap berries in the same type of packaging.