it is really hard to answer. What I can say for sure is logitech has better built quality and material usage but that zowie probably is more controllable. Comfort wise logitech is a bit better imo.
For hardcore/tryhard gaming zowie is a bit better but if you want the comfort, quality and the honey you should go for the Logitech.
I could write an essay about it but overall for my be-pro purposes zowie is better but the g502 is very good also. (a bit heavy, a bit thick and harder to control it perfectly and it tires your arms faster)
I dont have a good grip bcs my wrist hurts a bit when keeping up 110-120 kpm on yprac xD Both on logitech and zowie but it comes earlier with the logitech. Its not medical problem i just strain on wrist but when I relax my wrist it goes out immediately.
Back in ages I used: MX518, Deathadder v2, G5, G500, G502, and that EC2-B.