Not sure if chances for repair over replacement depend on the nature of your valve problem. The faster you get into surgery supposedly is in your favor if you want a repair.
My surgeon attempted to repair mine, but there was too much regurgitation, so he put in a St. Jude (my choice). The valve leaflets had myxomatous tissue, so that may have been a factor. I had a sternotomy; didn't know about minimally invasive surgery at the time.
On the other hand, my husband's MV was repaired (May 10, 2007). His MV regurgitation was due to chords that had ruptured and a leaflet that had torn due to a sternum fracture caused by airbag deployment during an auto accident. I shopped for a surgeon who could do a port-access incision (under right breast, between the ribs) instead of a sternotomy.
My left atrium was enlarged significantly and I was in bad shape because of the damage to the heart. John's had enlarged some, but otherwise he was in good shape.
If you can find a surgeon who has a very good track record with MV repairs via the port-access (Heartport is a trademark term), go for it. I believe it's less painful than a sternotomy and you should recover faster. A nurse at Dallas Presbyterian tried to tell John & me that more patients claim it's more painful, but when I asked her point-blank, "Have you ever had open-heart surgery?" she didn't answer. I told her, "I have, and I know a sternotomy is more uncomfortable."
It's hard to believe that my husband had heart surgery just 2 months ago. He looks terrific, has resumed all activities (except mowing our 1-acre lawn -- neighbors are doing that, bless them!).
Overweight people or large-breasted women may not be candidates for minimally-invasive surgery, since the incision is under the right breast.
Good luck!