In October, I completed MII's online self-study course for Master/Mate NC and Sailing Endorsement and passed the exams. The 90% pass rate on rules of the road is a challenge, though their placecard study aide really helps. Navigation
is not difficult once you understand set/drift, speed/time/distance; however, the practice charting questions took a good 10 hour day to complete. I found with multiple choice, if you you are off by the width of a pencil lead or 1/4 degree, you'll be between two answers. I ended up using a .5mm mechanical pencil and checking everything 3 or 4 times. Have a big erasure! Be prepared to slough through dozens of CFR sections till your mind is numb on minutiae . The Deck/Seamanship/Fire/Lifesaving makes sense once you've been on a boat for a while and (if you had enough time) you could lookup the answers in the CFRs. I felt there were patterns with the questions and answers and kinda got in a groove.
Overall they do a good job and I'm sure you'll succeed. Let me know if you have any questions,