I'm splitting this off from the "Spyderco" thread as it's a tangent, but want to make a couple remarks in the wake of the recent "rediscovery" that the LV honing compound contains larger Al-Oxide particles.
As noted in the other thread, the LV honing compound is very cheap as abrasives go, at $0.07/g. That puts it at about 1/100th of the cost of quality diamond pastes, and 1/7th that of the pure Cr-Oxide paste that Stewie cited. The thing to bear in mind is that that price point doesn't really support expensive processing or process controls.
As also noted in the other thread, the real-world performance of the compound in question is MUCH better than implied by the "300- grit" specification that its ultimate manufacturer provides.
What I think is happening is that the grinding process for the Al-Oxide in that paste actually produces very small particles the vast majority (and perhaps even all) of the time. Because of the price/cost constraints they're unable to do anything fancier than sieving to grade the resulting particles, and as a result the finest grit they can specify is the size of their sieve, hence "300-". In my experience as a (former) mechanical engineer this sort of thing is very common in cost-constrained products. While you may achieve some level of quality the vast majority of the time, you can't afford the incremental cost to do what it takes to formally claim that as your specification.
What I'm driving at here is that I wouldn't read too much into that spec. As I've said many times, based on my own experience I don't think the stuff is really "0.5 um", but it definitely isn't "300 grit" either. If it's working for you then stick with it. If you haven't tried it and you're on a budget then you probably should at least give it a go, because IMO it's good enough for (most) woodworking and the value is unbeatable.
You can get finer edges with a good polishing stone or tightly-graded compound, but I'm still not convinced that matters for anything but planing competitions and bragging rights. Full disclosure: I'm obsessive enough that I use tightly graded films and pastes much of the time. I'm just trying to be realistic about what all of that buys me (mostly speed IMO).