so, mechanically
Athelas mossball:
scales the best, starts out the worst. As of right now it gives us .19 dice per action with a dc of 15, .49 for a dc of 11. for a pool of 12, it gives .69 for a dc of 15, 1.21 for a dc of 11, 1.60 for dc 8. very good long term as it scales with transfiguration and isn't diluted by charms or reducing dc, ok but not the best right now.
Oolacile Myconid:
best at the start, scales ok. right now for dc 15 gives 48 average progress, which corresponds to 1.23 dice, for dc 11 gives also 48 average progress, which this time corresponds to .85 dice. for a pool of 12, at dc 15 it gives 140 average which corresponds to 3.6 dice, 2.4 if we are at intermediate transfiguration. at dc 11 it gives 140 which corresponds to 2.5 dice, 1.65 with intermediate transfiguration, at dc 8 it gives 119 which corresponds to 1.7 dice, 1.2 with intermediate transfiguration. good now, but doesn't scale with transfiguration and actually gets worse if we increase charms or reduce the dc of an action
Azure Floatvine:
starts barely better than the Athelas, scales the worst. right now for dc 15 gives .4 dice, for dc 11 gives .41, at 12 dice gives .24 at dc 15, .22 at dc 11, .27 at dc 8.
Overall, Althelas scales much better in the long term, but will only overtake the Myconid toward the end of the year. The Myconid is by far the best for now. the Floatvine is worse than the Myconid at literally any point, and is barely better than the Althelas right now. Personally I'd prefer the Althelas because I really like its long term scaling
Edit: If we get apprentice transfiguration as well, the Athelas, with a pool of 12, gives 1.27 for dc 15, 2.05 for dc 11, 2.64 for dc 8, so it scales a bit faster than I said earlier.