Ball bearing vs slide bearing

D Duckie

Both designs have their advantages and disadvantages.
There is really no perfect design of anything when looking at it in totality as everything is a compromise to varying degrees.

I can't speak to the Omega choice to mix designs but Rolex used well proven jewelled Slipper bearings on the Rotor axles of their workhorse movements for a good number of decades, before completely transitioning over a rather long period to Ceramic roller bearings with the introduction of totally new movement designs and finishing with the introduction of the 32xx movements.
I think if it weren't for the use of Ceramic rollers the change may not necessarily have happened as the new material has proven beneficial for a number of sound reasons in a number of applications with the most notable being the IWC Pellaton winding system.

Yehoshua

Thanks. But beyond theoretical discussion of advantages and disadvantages, enough years have gone by to draw some conclusions regarding servicing: does each tend to hold up problem free in practice for 5, 7 years? And surely a watchmaker has statistics at least for his personal experience.

D Duckie

To more directly answer your question. Yes both designs hold up equally well when the watches are serviced in a timely manner or across the array of industry service intervals which are recommended by different manufacturers. Though there is a wide array of operating parameters between different individual's watches that are virtually impossible to account for on any level so direct comparisons are hard to make.
I doubt watchmakers would bother with such trivial pursuits as to keep records.
Besides a single watchmaker could not provide a broad enough set of statistics to be conclusive and little more than anecdotal at best.
Why not write a letter to Omega, Rolex, Seiko ETA, Selita, etc, etc and pitch your question to see what they come back with😉
Other than that there are reviews on the internet that address some key aspects surrounding the question you are posing with a least one noteable watchmaker's comparison between the Rolex 31xx and 32xx movements.
You may or may not agree with the conclusions of professionals but there you go. Conformational bias is a powerful motivator👍

Knock yourself out and get back to us as to your own conclusions after a good old fashioned Google or two👍
The information is out there if you try hard enough😀

AlI i can say as an end user, is that I have had both types over many decades and found that the same limitations apply to them from the end user perspective with no failures either way despite the odd bump, knock or serious accident(which theoretically should have done serious damage). Though I do know which one I prefer on the wrist.