For keeping up to date on trackball info, I occasionally visit: https://www.trackballmouse.org/
I currently switch among these three:https://www.trackbal...low-laser-trackball/https://www.trackbal...ington-expert-mouse/https://www.trackbal...dpt1mrxbk-trackball/
The first two are nice in that each can be easily used with either hand. The Kensington's scrolling is probably easier for most folks, but I've found over the years that the buttons don't seem to last (I've gone through multiple devices, so I suspect it's the way it is with this model). The scrolling for the CST took some getting used to, but is the smoothest I have experienced.
After some practice I was able to use the third device (the DEFT Pro) with my left hand without too much trouble. (I'm not left-handed, but have found that typically keyboards with keypads make having the trackball on the right kind of awkward, so got used to using a trackball on the left.)
I had avoided the DEFT Pro and similar right-handed-only-ish trackballs but it appears that in some cases the barrier is not one that cannot be overcome.
I prefer to have a wired experience, but the DEFT Pro is flexible in that it can do that as well as Bluetooth as 2.4 GHz wireless via a USB dongle. I tend to take this one when traveling as it's smaller than the other two, and the non-wired experience can be handy when the micro-USB cable it comes with has been put to use to charge some other device
It's true that all of these devices are rather pricy. Occasionally, I see a good discount though.
I sometimes use: https://www.trackbal...bit-wireless-mobile/
, but find the scrolling "ring" area to be difficult to use.
I used to use: https://www.trackbal...ll-with-scroll-ring/
, but one of its buttons failed and I wasn't keen on repeating that experience so soon. If the build quality were to improve, I would go for this again over the Orbit Wireless Mobile, because the scrolling is much better. Neither have 3 buttons though, which I've come to appreciate.