How is the YouTube video going? I hope you aren't busy drinking teaThe QMK has the better eye relief but it's also a lower magnification so that comes with the territory. I'd say about 0.75" to 1" more eye relief than the TA31.
I'll be doing an optical quality review on my YouTube channel once my better camera equipment arrives. I wouldn't mind sending the optic to somebody that does durability testing, but some of these guys have unrealistic expectations. Even the ACOG can break. xD