I have a Canon OC-E2 (ie screwdown version), 3 Pixel FC-311 and 2 Yongnuo OC-E3/S cords. The Canon is the heftiest, the Pixels marginally the lightest and Yongnuo the only ones with lever clamp. All 6 work perfectly, every time. Internally there are variations on the theme but nothing of any moment.
Of the selection, I use the Pixel most because they are small and neat but they do remind me that I have fat fingers every time I come to wind the clamp down. The Canon lives clamped to my CB bracket so no need to comment on that. The rubber gasket (easily removed) on the Yongnuo sometimes makes me wonder if it is easing the pin contact more than it needs but it's never actually been a physical problem, only something in my mind. The lever action doesn't always 'latch' very positively when swung over but as the function is primarily to drop the locating pin into the corresponding hole, it really doesn't matter overmuch.
I'd be perfectly happy with any of those three makes - for me it's nothing more than what is available at the best price at the time I fancy purchasing.
PS No experience of Flashzebra - anything from the US comes to UK with stupid-money carriage charges so just never even gets considered. (ie something recently was $6.50 for the item and $39.88 carriage - guess who didn't buy from that source!)