Unfortunately, any given procedure type isn't necessarily better or worse globally, it just all depends on the experience, skill, and even judgment, of the individual surgeon. In fact, many leading surgeons, such as mine, still prefer a full sternotomy, even after experience performing minimally invasive procedures. His reasoning was that the advantages of minimally invasive (such as reduction in blood loss, trauma, infection, and length of hospital stay) were still not a fair trade off, in his eyes, for some of the potential compromises to the operation itself. For instance, he mentioned that national data have actually shown double the surgical stroke rate. Now, on the other hand, for isolated AVR, a mini sternotomy is pretty much standard at places like the Cleveland Clinic. I don't know, but I would assume, that they may have their own data refuting my surgeon's argument, given the high level of experience and skill of their surgeons, which is certainly known to be well above the national average.
Anyway, I'm sorry I'm not answering your question more directly, but I would just recommend, if you haven't already done so, that you ask both surgeons to be absolutely specific (including rates of all possible complications) about the pros and cons of their approach in comparison to not only the other, but also to a full sternotomy. They obviously wouldn't be doing it without very good reason, and maybe hearing their full reasoning and clinical evaluation will help you better decide.
If you're still not sure, I guess maybe one way to look at would be this: which surgeon do you otherwise have the most confidence in? When it gets down to it, there are probably lots of much more minor surgical details that we never bother considering, but which individual surgeons do somewhat differently. At least in my view, I think choosing a surgeon inevitably involves trusting them to make the right decisions, those we are aware of and those we are not.
Medical phobia or not, in many ways this is all toughest for our spouses. I was 35 at the time of surgery, and have young children as well, so let me reassure you that once you're in recovery, smiling and laughing, everyone is going to be just fine. Kids probably help more than anything keeping everyone's spirits up through it all. Best wishes.