I recently got 1/4 and 3/8 Koken wobbles to replace most of my 30+ year old Snap On and newer SKs.
In 3/8s, the Kokens increase diameter above 10" - which is a great feature. SOs 11" and over, while nice and skinny, turn into a torsion rod. When the nut/bolt breaks loose, the shock bounces the reverse lever on my ratchets, particularly the older 30 tooth SOs (not so much with Dual 80s). That's why I got the SK - but they're all the same chunky diameter.
Up to 13mm, the SO wobble plus doesn't seat fully on SO sockets - they get hung up on the broaching "mushroom". The Koken seat fuly, though - the male end is a little shorter.
Then, there's the Koken female end knurling. Like Vessel screwdrivers, the knurling is the "killer feature". Knurling on SO isn't that aggressive and the SKs are annoyingly inconsistent.