I only have one of those expensive suckers, and the user experience has been 'awkward'?
I use it on the tray built in to my trainer so I can interact with the app I use. It used to fall off the try, so I leave it plugged in and at least have a leash to drag it back to post. (I put a piece of 'Gekko-skin on the back, and it slides a heck of a lot less) The other problem is that I sweat 'a lot', and if I get any sweat on the pad, it freaks out. I lose control, and have occasionally had errant selections while riding. It's really a PITA when it happens. I thought of using a mouse, but the sweat would likely puddle on any mouse pad, and cause hydroplaning and gunk up the whole thing. I can't think of a better solution. I don't use the trackpad 'a lot' during rides, but it comes and goes. Sometimes I have to use it quite a bit, and other times rarely touch it. I also use Music to play tunes while riding, and have to use the pad to 'swipe right' on tracks I don't like. (Wasn't there a way to exclude certain tracks from playing in a playlist?)
How can I get around the 'sweat factor' issue, and not have a problem interacting with the app. A keyboard is out as there isn't room for it. I have seen where some people use tables next to their setups, but I don't have the room, plus can't imagine the feelings of claustrophobia and problems hitting them with knees and such, and I'd still have sweat. (I find gunk on the iPad screen too, nauseating at times. 'What IS that stuff?' And if it drys on the screen I almost need a chisel to get it off! And the back of the iPad?🤢🤢🤢)