I am going to ramble a bit on this topic.
Have few different trackballs, ms explorer, logitech marble mouse, cst2545w, itac trackball, ch products dt225 & rollermouse (NOS). I will come to the CST after I talk about these rest.
MS explorer, ergonomically the best, uses those tiny ruby jewels. My used one rotates free with the flick of a finger, but feels flimsy due to its age and thin (at that time) plastic. Replace the bearings, use gently and it will last you another decade. Not much DPI, so no dual monitors.
The itack uses real tiny bearings and if you find a nicer new one with a good bearing, it will move very nice, well designed and fairly free gliding. Also has no dirt issues as it is the ball to rotating rod contact. Construction wise it beats all the trackballs. Solid mechanical design. But not so high dpi as CST and I suspect it may not have any acceleration at all.
CH DT225: same as above but even better.modern design. Also take lesser space. Only weird issue is the NOS one I have while sitting in the box for 15 years has bearing sound, may be the bearings gone dry. These guys are sitting in the stone ages and still have the same 400 DPI.
CST 2545: nicely made trackball, but I have few cravings: even though the scroller is a free rotating scroller, it feels cheap and loose and I find my hands are not getting used to a completely free wheel, rather very little friction is needed (guys who are using rollermouse may know what I mean). The second thing is for such a nicer and expensive product the mounting screws pretty thin and the mounting studs are garbage. Infact when I called the company to ask about changing the ball to a colored ball, the rep first told me not to over tighten the screws. Believe me I tighten like a electronic device, not like a mechanical device using tiny screwdrivers with two fingers... but still one screw stripped the hole. It seems like they are using soft cheaper plastic, not the ones used by CH/logitech or used in older keyboards, definitely not ABS. But the good thing about them are high dpi. Now compared to my other used trackballs this one is pretty tight and not free rolling, but may be it is a new one and will take some time. The last point the rep told me is the ball is not swappable as this is designed for laser, other balls are for optical. Have not tested this.
The cheaper CST ones are optical and have max 800/1200 dpi. A lot for single desktops but some crazies are using 3 monitors. Not for them.
The kensington expert mouse is the other one I like very much... I wish I can do something to that garbage scroll ring they are making with some salvaged/outdated die and it is hit or miss when you buy the EM, some have a smooth scroller and others garbage. I have 3 of them, the best one has 3 scratchy spots and the worst one scratchs and gets jammed all around.
My take is the ruby/jewelled ones beat the bearing types unless you can source the original high quality bearings and put them, the stuff we are getting now a days are chinese garbage with chinese packaging or same chinese garbage with european packaging and high markup. Dont know which one is better
, but ebay may have some of those NOS bearings that might work, but big bucks needed.
