I have an Icemat, in its rebranded Steelseries Experience I-2 form. Wouldn't use anything else for a modern mouse, but god help you if any hard dirt or grit gets between the mouse and the glass surface, because the scraping noise will drive you nuts.
Shame that Icemat/I-2s are so stupid expensive now, though... just like 15 KHz RGB CRTs, GDM-FW900s, Amigas and X68000s. Everything I like is going up in price! I remember when these things were $40-50 still, with the cheaper ones often being the pink ones.
There should be newer tempered glass alternatives available after Steelseries quit making 'em, I just have to remember what the names are. Some are custom made specifically to be mousepads, others are just cutting boards adapted into mousepads.
As for the original topic of ball mice, I'm not a fan of 'em, but I do have to use some old-school Amiga tank mice and Mac ADB mice because I don't have appropriate adapters for using more modern PS/2 or USB mice on either. I do note that some ball mice have nicer metal rollers, though, particularly the boxier Apple ADB mice.
Also, someone linked one of the classic Logitech "bear claw" mice above. I picked one of those up from a thrift store a few months back just for the nostalgia factor, as they are pretty ergonomic and give me fond memories of other people's setups from my childhood. It also might support RS-232 serial with a simple pin adapter if I ever find myself with a system so archaic it doesn't even have PS/2 ports.
One thing that stands out is that even with a proper cloth-over-rubber mousepad that would've been used with ball mice, these things suck when it comes to fast movements, as the ball doesn't always keep a grip on the rollers when flicking the mouse. Optical is a godsend for the entire FPS genre, and it makes me wonder how those old Razer Boomslang mice held up before its optical successors took over.