Thanks for all the replies.
As initially noted, my current truck (which will be gone when the new one arrives) has a solid cover (extang? maybe, the nameplate fell off two days after I bought it, so have forgotten), which is strong enough to stand on and has never leaked, even in downpours and car washes. The only issue is inability to carry large items, like furniture etc. without completely removing.
The one I posted about folds up to within 6 inches of the cab and, in a couple seconds, can be fully removed from the rails, which remain with the truck bed. For a tonneau, it's a bit pricey (over $900 USD), although the solid one cost me $1200 CDN. And it has a lock and key (although not sure how effective that is).
I would prefer a hard, rather than soft, cover, but could be persuaded otherwise.
Marv.