I use Anki everyday for medical school and for personal learning-- geography, notes from books I've read, research ideas I've thought up I want to review later, etc.
If you put in the time (I do at least 45 minutes of Anki a day, which turns out to be roughly 300 cards, 50+ of which are new) and you're consistent, the volume of information you can retain is truly staggering.
I have a retention rate of 90.1% and I've learned 15000 cards over the last 16 months.
About 2000 of those cards are my own-- the rest are fromv arious premade medical decks. Using premade decks is perfectly fine, but you do need to make you get a first pass of the material through some other method first-- Anki is not ideal for learning material, just retaining it.
Mnemonics can be successfully integrated into Anki cards-- but I think they're best for information that's easily confused with other bits or for really tedious stuff. Example: remembering which random medical drug is best for which genetic mutation, or which chromosome is mutated in which disease. Stuff like that is just pure tedium-- so translate it into images with the Major Mnemonic System or into memorable images like Sketchy Microbiology does.