One key difference, that you can see in the photo, is that the BV uses buckles instead of Velcro on the straps that attach the bag to the underside of the saddle, something much more important than it may seem. A pair of bike shorts (or any shorts) will shred quickly if they’re rubbing against that tiny bit of Velcro protruding from the side of the bag, and it’s sure to destroy expensive sweaters and gym clothes if you stuff the bag into your backpack or messenger bag.
Do not take your Bike to Kyle's Bike Shop they handled my bike so poorly they can not work on Vintage Schwinn' and the attitude they had if it wasn't a high dollar bike don't expect good service. I had to find my own parts, had to take the bike back twice to get the wheel trued and they ruined my bike it is so scrapped up the Schwinn is gone on the side of the bike. If you care about your bike do not take it here.
The fabric attachment system is low-tech, but that seems to be helpful, as it can adapt to seat rails of different widths. One fancier option you might see on more expensive seat bags is a quick-release mount that you install under your saddle. But those have a fixed width, and therefore can fit under seats with only those exact specs. Brooks saddles, for example, are too wide for these mounts.
2) On my second day, the pannier bag fell off and got lost after I stopped for lunch, which required locking up the bike somewhere, so I took the bag into restaurant and re-attached it using the two velcro straps on the rear rack. I've used many panniers before, thought I did it correctly. But apparently I did not. So I paid $55 (cost) to replace everything in bag and bag. In hindsight, I wished I'd put a bungee around bag straps to really secure it to bike. PROBABLY MY FAULT.