To transplant or not to transplant, that is the question, that most of us struggle with. It is really good that your husband has gone through 10 Vidaza cycles. There have been a lot of good studies about optimizing the timing of transplant based on the status of the patient's MDS.
http://www.mdsbeacon.com/news/2013/0...fe-expectancy/
The basic thrust of this article is that depending on how aggressive the MDS is, it may be more or less advantageous to do a transplant. The summary of the article is that people with lower risk disease should generally hold off on transplant, while people with more advanced disease should generally go forward with the transplant, taking into account other issues like the availability of a donor, and overall health. This is speaking strictly from the law of large numbers, and really does not address individual cases, which is what always makes the decision challenging.