
A comparison to using Rite of Seeking (4), assuming no support for either and you always have a location available for an additional investigate, at discovering 18 clues:
- Rite would take 10 resources, 2 cards, 2 plays, 6 investigate actions at 3 clues per actions
- Sixth sense would take 3 resources, 1 play, ~13 investigate actions, at 1.35 clue per action
Rite of Seeking saves 7 actions, but costs 7 resources, 1 card, and a play more. A naive analysis liquidating every resource and card would into actions put Sixth Sense squarely ahead. Even a slightly less naive analysis — say you spend a play on Emergency Cache and put a copy of Rite of Seeking in play with an Uncage the Soul — still works out to +1 resource +3 cards and +2 plays vs +7 actions, putting Sixth Sense only 1 investigate action behind (assuming you can use the resources and cards to save actions in other ways).
This comparison purely theoretical — there's almost no scenario where you'll need to get 18 clues alone as a mystic. But it's quite common to need to need to get more than the 9 clues that a single copy of Rite of Seeking would get you; which gives Sixth Sense a even larger lead in such a situation...
...at least, until support is factored in. Sixth Sense's support options are just worse:
- Dark Prophecy adds +0.5 clues for a card and a resource.
- Grotesque Statue (2) adds ~+0.3 x3 clues for a card, a play, and 3 resources
- Eldritch Inspiration adds +1 clue for a card.
- Olive McBride + Ritual Candles — adds at +0.4 clues 1/round for 2 plays, 2 cards and 3 resources.
When compared with Recharge or Twila, no amount of support Sixth Sense can get will keep up with Rite of Seeking's action compression. The caveat is that recharge support costs XP.
Other considerations:
- Rite's downside is easily mitigated most of the time, the real downside is that a failed Rite of Seeking test is much worse than a failed Sixth Sense test and it's terribly inefficient when there's one clue remaining (Seekers, do your job!)
- Potential shroud reduction is occasionally useful, but offset by the fact that it needs to make more tests at a high shroud location, to the point where Grotesque Statue is more useful for Rite of Seeking than for Sixth Sense.
- Playing Grotesque Statue to speed up Sixth Sense investigation is usually a wash on clues/action compared to just taking an extra Sixth Sense investigate
- Sixth sense is worse on scenarios which require you to clear clues off a single location to advance, and on VP locations
- Jacqueline Fine can use Sixth Sense better than any other investigator
So in conclusion:
- If you're going to get recharge tech for your other spells anyway, go for Rite of Seeking
- If your team has a competent seeker and you don't need to get much more than 9 clues a scenario, go Rite of Seeking (Sixth Sense/Drawn to the Flame can pick up a few more if needed).
- If you're in a low XP campaign (read: Dunwich) without Arcane Research, or have other priorities, Sixth Sense becomes much more attractive because of how little XP it takes to get going.
- Sixth Sense is far cheaper to run and allows you to run a Mystic deck with much fewer economy cards.