I use Mochi with all settings out of the box. Mochi doesn't even implement the SM-2 algorithm, it just applies a multiplier to the review interval on getting it right/forgetting.
I spent so much time and effort comparing the various spaced repetition software before finally, grudgingly, choosing Anki over Mochi.
My rationale was that, while Mochi's UX is amazing, the algorithm matters. SuperMemo seems to justify this - SM18+ is a highly refined algorithm and 'seems' to provide much, much better performance than SM2/Anki.
So Mochi's incredibly basic 'engine' seems, by this logic, to be a pretty significant downside.
In the end what I care most about is memorization, and it seems like the best 'engine' for that is (Supermemo if you're on Windows, otherwise...) Anki + FSRS.
I'd appreciate being convinced I'm wrong - Using Mochi was a vastly more pleasant experience than using Anki.