GG, thanks for pointing out the similarity of the Sony HX99 to the Casio 800/850 models. With no replacements possible, I am concerned that the failure of my ZR800 will one day eventually need a replacement with similar capabilities.
Currently , I like the ZR800 for its remarkable image stability, so that I can get good hand held shots even when travelling in shaking vehicles. A folding ClearViewer attachment simulates an EVF, to overcome the lack of a viewfinder, both to help avoid screen glare, and add stability by resting my camera-holding-hand against my head. Multi SR Zoom also allows me to match the HX99's reach. I also use time lapse quite a bit for continuously tracking roadside scenes when travelling by vehicle through new locations.
Although I don't find the Art settings useful for my needs, I do appreciate the Best Shot mode, for quickly accessing the best settings for a variety of situations without having to fiddle with manual choices: the HDR, HighSpeed Anti-Shake, and High-Speed Night Shot in particular. But I'd appreciate the 4K video of the Sony.
At the moment, I complement the ZR800 with a ZR5100 (and ClearViewer) for the 19mm wide lens and slightly larger sensor, and their added convenience for cramped, dim, interiors. The similarity of size, weight, menus and interchangeability of batteries are also convenient. But I have not yet found a need for the flip-up screen, though the front shutter button has advantages (and the disadvantage of inadvertant operation!). The two cameras give me greater scope, and backup in case of failure - or being caught with a brief opportunity just when a memory card or battery needs changing.