For the last few trucks I had before I bought my 2019, I always had bed caps / shells. We had a large dog at the time and it gave him somewhere to ride so he could move around (all had sliding glass for air movement) and still gave us plenty of room to use the bed for hauling.
When I bought my 2019, we no longer had a dog but I still wanted a way to secure items in the back (mainly to keep them out of plain view) so I went with the BakFlip MX4 and couldn't be happier. I can secure items under the cover when needed and still carry larger items by simply folding it up or using the rods to support it against the rear of the cab. I have found one place that appears to have leaked a small amount during a 'monsoon' of a week that we had recently but it was minimal. If I'm carrying things like luggage in the back, I always use plastic totes for ease of loading / unloading and for added peace of mind knowing that those items will stay dry.