I had a littmann cardiology III for the past 8 (? Ish?) years and decided to upgrade the other day (a little birdie told me that my work would pay for it
). A doctor at my work uses the master so I tested his out but I'm not a fan, I prefer having both the pediatric and adult bells. I have heard vets recommend the master of you're interested in mainly pursuing equine/LA exclusively; cardiology IV if planning on SA/mixed.
If you plan on paying out of pocket for your, I would potentially wait and see if there are any reps that come into the classes and offer discounted ordering for first semester.