It really depends of what you want to do with it.
do you want a period correct mouse ? What surface are you using ? (table, mousepad)
Do you want a specific mouse to match the PC case / keyboard. (I'm using an original IBM PS2 mouse on one of my system because it looks great with the model M keyboard and the case.... even if i don't like how the mouse feels and its ergonomics)

Most of the time i use a random usb mouse or random PS2 ball mouse if USB is not an option.

One of those early/mid 2000s white logitech optical ps/2 mice. You can find them NOS on ebay for pretty cheap.

I can vouch for the Mitsumi S6702, generic yes but resistant and reliable.

Using a Logitech MX400 laser mouse with my retro computers. Does PS/2 with a "dumb" adapter, and works on any surface.

eyalk4568 wrote on 2024-06-08, 16:05:

Also would you recommend a ball mouse or an optical one, because I heard that the older optical mice were horrible is it true?

I don't know if all early PS/2 and USB optical mice were terrible... but the few I do remember using and that I have are indeed pretty terrible.
So I'd definitely vouch for going for a ball mouse... but ONLY if it's a Logitech.
Why, you ask?
- Because Logitech ball mice use X/Y pickup/transfer wheels with larger contact diameter. As such, this gives much better contact with the ball's surface so you don't get random X/Y drift like many other ball mice do. To offset the lower sensitivity from the X/Y wheel's larger contact diameter, Logitech has made the pickup/transfer wheel with finer slot pitch.
In short, Logitech's ball mouse design is superior... and FWIW, I've only seen Logitech do it like this. Most other ball mice use skinnier pickup/transfer wheels with much coarser slot pitch.

kingcake wrote on 2024-06-08, 19:36:

One of those early/mid 2000s white logitech optical ps/2 mice. You can find them NOS on ebay for pretty cheap.

+1

M-S34 and M-S69 is what I use almost exclusively for all of my retro computing needs... and even on a lot of my non-retro systems too. In fact, my "contemporary" gaming rig is equipped with an MS-69 as well. Back when Fortnite was still a popular game among both kids and adults alike, I always made people laugh when the usual question was asked, "what are you playing on" and I told them I'm on an old PC with a ball mouse and a CRT monitor. 🤣 It was even funnier when I clutched a few team saves and we managed to get a win / victory royale because of it. I've also tried some better lazer mice, but I can't say I play/aim better with them with my ball mice... so in short, I don't think quality ball mice are that bad... well, Logitech in particular.

And yes, they should be relatively cheap to get on Ebay as NOS.
Or, if you're not afraid of screwdrivers and aren't against putting in some elbow grease, you can get some used mice and refurb/clean them. Most older Logitech ball mice take apart with 1 or 2 screws and are relatively easy to clean. That's what I did when I got a box of them (lot of 13 mice) for the price of shipping. The M-S69 models are pretty tough, in particular, so it's very unlikely you'll get a non-working one. They use Omron or similar high quality brand buttons.

acl wrote on 2024-06-08, 18:23:

What surface are you using ? (table, mousepad)

Excellent question that really needs to be considered, especially if going with a ball mouse or an optical (red LED) mouse, especially the early ones - they don't like shiny smooth surfaces.
Actually, whatever mouse you get, you should still consider getting a proper mousepad.

...I heard that the older optical mice were horrible is it true?

I wouldn't call them horrible, but the newer ones are indeed better. I got my first optical mouse in late 1999, a MS IntelliMouse with IntelliEye. I liked the mouse very much, however I remember that when moving it very fast Windows lost track of the mouse and the pointer went all the way to one of the edges to the screen. With the successors (MS WheelMouse Optical and MS Ready Mouse) I never encountered that issue.