Q1: do modular cables differ meaningfully in quality?

They can. But for the most part, they don't. You can get hi-tweak patchcables with all sorts of voodoo to 'em, but those are somewhat pointless; using silver Mogami cables or some such makes far more sense on LONG cable runs, and not little 1m or less lengths.

At the same time, my skepticism about audio cables still stands. The only place I use something like that are the OFC lines from the amps to the monitors, and there it's mainly due to the fact that those big 12 - 14ga lines pass amplified audio much better and don't pose a resistive load like, say, cheapo speaker 2-conductor lines from Menard's. But at the same time, I have used that low-rent speaker wire for things such as a few amateur radio antennas...and even with the 10 watt signals I put out (I like low power operation...more of a challenge), I can still hang with other stations running ten times that...or more.

The one point where they DO differ, though, is in build quality. Some cheap patchcords really do feel like they're about to fall apart in your hands, either due to using a flimsy cable stock, or janky soldering work on the plugs. That was the scary bit, but I opted to make the leap with these AliExpress ones because I didn't see anything about them that indicated that. And sure enough...really well-done molded plugs with molded-on strain reliefs at the plugs, and they use a bit thicker cable stock which is the sort that has plenty of flex to them...but which can also be easily manipulated to stay out of the way of things and stay there, kind of like what you'd get in the box with an ARP 2600 back in the day. So...

Q2: Lugia, you think these are as good or better than most modular cables?

Bet! After I had a close look, messed around with them and such, I was very pleased. Zero buyers remorse here. And like I mention above, I really like the feel on the cable stock. It's got plenty of flex...but it's not limp, as you can shove it all around and it'll largely retain the position you leave it in. And those prices are really the cherry on the cake here, tbh...the cables are pleasing enough, but the money saved on them? Daaaaaaaaaamn...