I don't remember precisely, but I think it was in the +3 range. Diagnosis was not after a stress echo, but I had been getting echo-cardiograms on a yearly basis because of the prolapse to see if things were getting worse; they had been monitoring this for a few years after my EP heard a heart murmur (i.e., the leaky valve). The main reason to go with the mitral valve repair was because my afib, which had been controlled after my ablation, was popping up again. Mitral valve prolapse can cause afib.
Minimally invasive surgery was the decision of my cardio-thoracic surgeon. If it wasn't something he thought could be done with minimally invasive surgery, the alternative would have been a thoracotomy. Minimally invasive is apparently a bit more painful, but heals more quickly.
The only potential drawback was maybe not being able to place the mitral clip; he may have been able to do that if he did a thoracotomy, but that's speculation on my part.
If you do have the surgery, I would highly recommend getting into a cardiac rehab program afterwards; it will really help to figure out what you can and cannot do and get you back on your feet.