I’ve said this before, probably on this thread, but Bristol actually persists a lot longer for me than Jewel. Jewel “runts out” on me after maybe two good fruiting seasons. Bristol is still going in year five.
Although Bristol is more susceptible to anthracnose, I read once online that it’s less susceptible to a lot of the viruses that affect black raspberries than Jewel, and that seems to be what’s going on in my garden.