The Northwestern Review is a complete scam in my personal opinion. It was offered at our school and a guy basically read off a powerpoint but went twice as fast normal lecture speed to cover the material. It certainly doesn't suit visual and kinisthetic (learn by doing) learners. I knew some people that liked it but they are the type who can kick back, listen and absorb everything. He doesn't really teach either. It's assumed you know the material so he just reads bullet points outloud.
Boards Boot Camp isn't much better. The materials they send you include books you already own like Boards and Wards, Case Files for OBGYN and Peds, Boards Busters question book and things of that nature. They do have some question books and an online q-bank that offers questions that are nothing remotely close to resembling real COMLEX questions but they are helpful in their own way. I would just subscribe to their online question banks and save money. I know someone who liked it because they map out a plan for you that tells you what to read on what day and what questions to answer in what. It can provide structure but you need at least a month to do it and realistically about 2 months.
I would definitely recommend Boards Boot Camp over the Northwestern Review by far but if I had to pick a strategy that is the most effective, I would argue doing comquest and combank and making sure you know your OMM well. COMQUEST is such a good source that I still use it to study for my 4th year clinical exams since we don't take the shelf at my school.