so if we put it personally, for me air max shoes are the most comfortable shoes ever and i'm quite a sneakerhead in the less lucrative way (i just love sneakers). I bought many reps and i can't tell the difference with original in terms of comfort
furthermore quite a lot of us here bought rep yeezys and the response is clear: "most comfortable shoes ever"
So if you tell me QC is better on gen in terms of details I might agree, in terms of material and machinery used to fabricate the shoes, I'm sorry, I do believe they are the same for gen or rep.
I feel like jumping in here because i own various Ali shoes of which i have the gens too (just in separate colorways).
Roshe - Reps are very comfortable but 3 pairs have had issues with stitching on inner side creasing in and causing severe blisters when running. Gens no such issues on 2 pairs. The sole on the gens is far more pliable but the rep are still comfy, its just the gens are more so.
Air Max 95 - Night and day difference the inner sole (the mid layer?) is extremely hard when compared to the gens and the bubbles are usually deflated from day one. THe upper is of similar quality as gen, sole material slightly harder on rep making it less flexible. Occasional flaws on stitching of upper to sole causing them to seperate.
Air Max 90 - not too much in it but the materials on the gens are higher quality and thus more comfortable.
Shox - Probably the biggest fail. Mid sole is rock solid as are the shocks, definitely wouldn't run on them. Extremely heavy shoe when side by side with the gen.
Speed cross - Reps still comfy but less padding on the upper and heel, also not same climashield tech on the CS version. The insole is vastly different from the ortholite gen resulting in less comfort. Still comfy but significantly less so than the gen. They lace material is comletely different and overall the shoe will disintegrate way before the gen if used for the intended purpose.
Yzy - haven't tried the gen but seriously i doubt it can get much comfier than this.
Just in case anyone was wondering I find all the above true on sizing.