I switched from firecracker to osmosis, and that was the best choice for me during the semester I just finished. The space repetition is programmed much better with osmosis and the flashcards are much more relevant to what I am learning in the lecture, however, the same time also very closely linked to step 1.
Osmosis linked all my study material together: lecture slides from school, first aid step 1 book, youtube mini lectures and patient experience, wikipedia pages, and a huge step 1 question bank. Everything is just one click away in Osmosis.
The amount of the daily flashcards is very doable and played a big role in my ease during final exams preparation.
This is a great study tool and I wish I got to know this in the beginning of my basic science classes.