Blade finishes are something that a lot of people take for granted. Usually, the finish of a blade is chosen because of a user's preference in aesthetics and not their preference in utility, but it needs to be noted that certain types of finishes are appropriate for certain applications. Lets take a brief look at the different kinds of blade finishes available from a host of different makers and manufacturers, hopefully this will clear up any questions you have regarding the different finishes available on the market.
Lets start with the most common finish available on a pocket knife- the satin finish. This is a term generally used for an uncoated blade that's been polished either by hand or by machine to bring the knife to a nice luster. Generally, this can be done through the use of an abrasive like sandpaper or fine steel wool, and leaves a nice shiny finish that's appealing to 95% of users on the market. Since the blades are uncoated, they tend to not show wear as badly as coated blades, although in the right light scratches will be very evident. This is a cheaper finish to implement if done by a machine than something like stonewashing, which takes quite a long time, and most manufacturers offer satin finishes on their blades. It's a good all around finish that will wear well with time, although generally not recommended for carbon steels as it doesn't protect the steel from the elements and prevent rust.
It should be noted that there's a distinction between a regular factory satin finish and a hand rubbed satin finish. Hand rubbing is a term used to describe a specific type of hand polishing technique in which a individual sits down with a blade, often for several hours, and uses an abrasive to polish the blade in an even pattern. This is typically only seen on the highest end production knives and on custom knives, but this technique produces a very desirable pattern in the blade that collectors of fine knives desire above almost all other finishes. It preforms identically to regular satins with one caveat- it scratches extremely easily and scratches WILL show. Typically these finishes are reserved for knives that are collectables and not user tools.
Another subset of satin blades is the ScotchBrite finish. ScotchBrite is a type of satin finish that usually leaves a bit larger of scratches in the blade and doesn't show wear quite as easily. That said, this is a very economical type of satin finish that's typically found on cheaper knives like those produced overseas by companies like Cold Steel. It wears well and is very easy to apply as it is a machine applied finish, thus allows for a cheaper product in the end.
Stonewashing is generally considered one of the more desirable finishes on blades, particularly those that will be used heavily. While I do not stonewash any of my knife blades, many custom makers do because the scratch pattern created by the washing of the blade with stones creates an even and random scratch pattern on the blade and doesn't show wear. Fine stonewash finishes are prized for their beauty, like those seen on the Chris Reeve Sebenza, and do not show cutting wear as badly as say a satin finish.
Additionally, one may choose to bead blast a knife blade. While bead blast blades create more surface area on the knife and encourage rusting, this is a cheap finish to apply unlike stonewashing and satin finishes and bead blasted blades are near zero glare. Companies like Strider knives and Zero Tolerance like to bead blast their blades because of the low reflectivity, and in general this finish is preferred by the ultra tactical community.
When one starts to coat a blade, one must consider several different types of coating. There are a lot of quality coatings on the market, but there are four that I consider to be the highest quality and most wear resistant- Duracoat, Cerakote, Tungsten DLC and Benchmade's BK coating. I prefer DLC coating as it wears the best out of all four of these options, but all four are quality options when looking for a coated blade. While it may be a little more expensive to go with a coated blade, consider that it prevents carbon steels, like D2, M4, ect, from rusting and creates a low reflectivity which may be desired by some users. I won't go into the specifics of each individual coating, but they each have different application processes that differ from manufacturer to manufacturer, but the bottom line is the Tungsten DLC wears the best out of the lot. I, however, offer only uncoated blades on my custom pieces.