While this update was met overall with high praise, there are still a lot of details that aren't clear. I want to get the information I've learned out there and will happily update this post as I learn more. If you think I missed something, please let me know.
It's a fairly well known fact that not all infinite gathering tools are created equal, even when not accounting for the extra harvesting benefits. For example, the Consortium Harvesting Sickle has a shorter animation and actually completes the harvest partway through the animation instead of at the end. The Unbound Magic Harvesting Blast has a longer than normal animation, but harvests three strikes all at once.
Well, these benefits are tied to the skin itself, not the tool. You can purchase your typical Orichalcum Sickle from a merchant, transmute the skin onto it with no glyph, and get these benefits in harvesting speed or extra hits.
Suggested skins to use:
1. Consortium Harvesting Sickle: faster animation, can animation-cancel for faster harvest.
2. Fused Molten Sickle: faster animation, can animation-cancel for faster harvest.
3. Unbound Magic Harvesting Blast: gathers three hits at the end of the animation, good with the Glyph of Bounty (see below).
4. Unbound Magic Logging Pulse: Gathers two hits on the last strike, good with the Glyph of Bounty (see below).
5. Unbound Magic Mining Beam: Gathers two hits on the last strike, good with the Glyph of Bounty and Rich veins (see below).
Suggested skins to avoid:
1. Skritt gathering Tool: Roots player in place, making canceling animation (such as for avoiding attacks) difficult.
Some of the glyphs are fairly straightforward in function, namely the Industry (50% faster harvest speed) and Flight (100% faster move speed after harvest), so I won't be going over those much. However, others have more nuance to them.
Glyph of Industry
This one is pretty straightforward, dropping the normal harvest time by 33%. This is what a 50% speed increase does. I will admit that I have not personally timed this, so it is possible that my interpretation is incorrect, but that is how the phrasing of the description works out.
Glyph of Flight
The buff duration is 5 seconds, but it's important to note that you don't actually get to move at double-speed afterwards. Unmounted movement speed caps out at 400 units/second, which is the same speed as an out-of-combat player with Swiftness. To my knowledge, mounts are unaffected by speed modifiers altogether (Swiftness doesn't do anything on them). This is nice for harvesting in areas with enemies that attack you while harvesting as it gives you a better chance to get away.
Glyph of the Leatherworker/Tailor
I'm grouping these two together because their mechanics are identical. These give a 33% chance on each strike to generate a scrap of the appropriate material.
However, the original blog post for this update was a bit misleading on these glyphs in particular. In it, ANet said that the tier of leather/cloth you would get depended on your level and node you were harvesting.This is only partially true. The material tier you get is dependent on your level, but does take downlevelling into account. The node you are harvesting from actually has no impact whatsoever on what you get, only your (adjusted) level does. This is usually irrelevant, as you'll never find copper nodes in a level 80 area, but it does factor in when harvesting home instances. Keep this in mind when looking to collect certain materials. On the upside, these can get you any tier of material, including T6. T6 materials are rare occurrences, but they do drop from these glyphs.
Glyph of the Watchknight
Like the Leatherworker and Tailor glyphs, this provides a 33% chance per strike to get a sprocket. Unlike those two, there's only one tier of sprockets, so the entire second paragraph of the above can be ignored for this.
Glyph of the Unbound
This is currently the only glyph that behaves differently when placed on different tool types (not skins, types). When placed on a sickle, it gives a greater yield per strike of unbound magic. This is usually not a concern, since the other two tools hit three times (minimum) per node and generally even out, but it is worth noting. On picks and axes, it gives 1-3 unbound magic per strike and on sickles it gives 3-6 per strike.
Glyph of Bounty
This one seems straightforward, giving a 33% chance per strike of getting another strike on the node, but it has much more nuance than that. First and foremost, this additional strike itself gets the same chance of generating yet another strike. Theoretically, this can chain endlessly, but there is a hard cap of 3 extra strikes on any given node (4 total on plants, 6 total on saplings and ore nodes). Secondly, The unbound skins mentioned above will immedietly harvest this additional strike, with the sickle even immedietly harvesting a second extra strike. Third, because my testing suggests that the chance is calculated on each strike, this means your typical saplings and ore nodes have ~70% chance to get at least one additional strike. That said, I have a small sample size, so more testing is needed to confirm this.
It also appears that a node can only have one "extra strike" at a time. Once an extra strike has been generated, no more will be on that node until all "extras" are consumed. In other words, if the first strike on a sapling or ore node generates an extra, then the second and third will not do so. Once you harvest this "extra," you once again have a 33% chance of generating yet another. What this works out to on these nodes is a 70% chance of one extra strike, but only a 33% chance after that for additional strikes. Rich veins are an exception and do not generate extra strikes.
However, it should be noted that this glyph does have some limitations on the nodes it works on. It does not function inside home instances with exception of the Black Lion Garden Plot, where it does. It also does not work on Guild Hall synthesizers.
Glyph of the Scavenger
This gives a 33% chance of a fine crafting material per strike. I don't own this glyph myself, so I invite those who have to chime in and let me know if you have found any methods of predicting what it gives you.
Plague Signet is the only skill in the game that is worse when traited.