Let me go ahead and get the bad stuff out of the way. First of all, this stand is NOT the same level of quality as something you would find in a bicycle shop being used for the shop's repairs. it's quite a bit more flimsy, and the grip likes to rotate if you don't get the bike's center of gravity just right. The tool tray is also made out of a rather cheap plastic that can break easily at the rim. That being said, this stand is perfect for home users and makes mundane tasks like fixing a flat or cleaning the chain much easier. It easily holds my Raleigh Merit 3, and I don't worry about the thing falling even if the grip tilts a bit. The stand significantly shortened the time I needed to change an inner tube on my bicycle, and made me less worried about damaging something on the bike by jury-rigging a stand out of whatever I had lying around.
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.
Modern bottom brackets use a sealed bearing type construction that keeps water and debris locked out, so they seldom go wrong. Maintenance is impossible so they need replacing when they do wear out. Older style cup bottom brackets need to be re-greased every now and again, and occasionally will need to have their bearings replaced. There are a lot more teeth on the chainring cogs than those on the rear cassette, so need changing less regularly. Cranks usually a solid one piece construction so there is not much to go wrong.