I'm a big fan of just about any mouse from Logitech. It seems their designs are the most sane ones I've seen. That being said, their ball mice from the PS/2 era are classes above anything else... and on that note, I can understand why people hate ball mice. With Logitech ball mice, a lot of the shortcomings are not there or not nearly as pronounced. For example, Logitech uses larger diameter "pickup" rollers on the ball, so the ball cannot slip like it does on other ball mice that use thinner rollers. Also, the bigger rollers are less prone to picking up dirt... and it takes a lot more time (and dirt) before the mouse starts feeling "choppy". Lastly, the larger rollers reduce the perceived DPI from the ball... but to make up for that, Logitech uses much finer pitch transfer wheels. So the end result is a mouse with overall the same (or a bit higher) DPI than other ball mice, yet a lot more precise and steady.
And for all of the above listed reason, I have still (after 25 years) not moved beyond my 2-button Logitech M-S34 ball PS/2 mouse (I'm using it on the compute I'm posting this from right now.) Yes, it does lack a scroll wheel, which is a big bummer for modern browsing (and programs that use the scroll wheel... which quite a few do.) But other than that, it's extremely comfortable (despite looking a bit "square-y") and tracks very well. Also, being PS/2, it's great for any retro machine... and also some newer PCs that still have PS/2 ports.
My 2nd favorite / pick is the Logitech M-S69. This is basically just a more round and souped-up M-S34 - it has a scroll wheel and is more rounded in the corners. Comfort-wise, I rate it a little lower than the M-S34... but still above many other modern and retro mice I have tried. Because of the scroll wheel, I use this mouse on almost every semi-modern PC that can accommodate it (with a PS/2 port.) The M-S69 is what we had on just about all of the PCs back in high school and also in university. These are really durable mice with Omron switches that can take on a lot of abuse... which is also why my M-S34 from 1999 (the one I'm using right now) is still working.
The M-S34 and M-S69 are not the only Logitech ball mice I'd consider, though. Like I said, I find just about anything from Logitech (ball or optical, PS/2 or USB) to be very competently designed.
Now I will tell you the mice I have run into that I certainly don't like: any early optical Microsoft mouse - funny, given how many people recommended it here. But I find that too many of the early optical Intellimice like to randomly "jump" to one corner of the screen every once in a while. This is on multiple different systems with completely different software and hardware and with different early Intellimouse models. I never took the time to see what causes this, but I know I'm not the only one to have ever reported this bug with early optical Microsoft Intellimouse. The latter ones seems to be a little better... though recently I found a slightly newer MS Intellimouse, and I still had it jump around on me, but just a lot more rarely than the early stuff. FWIW, it was a USB type and not PS/2. But I don't think that matters. I also have a few PS/2 ball-type MS Intellimouse and those are... crude... in comparison to Logitech. They have small diameter pickup rollers and sensitivity as well as accuracy is MEH at best.
By the way, here's a nifty little retro / "museum" -like site I found a while back that shows the insides of various retro mice:
http://www.tcocd.de/Pictures/Peripheral/in_mice.shtml
And speaking of that website, here's how my beloved M-S34 and M-S69 look like respectively:
http://www.tcocd.de/Pictures/Peripheral/Logitech/ms34.shtml
http://www.tcocd.de/Pictures/Peripheral/Logitech/ms69.shtml