Rent to own is only good when the price of the house is going up.
However, I do not believe that is what is happening now. According to most economist(including builders) believe the price degradation is NOT over yet. And the downward pressure of the housing market will be here two more years. The unemployment rate will go up for another two years(per Obama administration project - check Youtube and graphs) and this will definitely negatively impact the housing price.
I tend to believe it is foolish to get in a rent to own agreement at this time. Just get into a regular rental contract and buy when the house price stabilize.
High end housing such as silvercreek area has not been impacted yet but it will get there. It will just take little longer to get there. As soon as many people no longer consider housing as an investment vehicle, it will slowly deflate its value.
I recommend that you just rent for a nice house for 3-4K per month. I expect the price erosion of 1 Million + houses to exceed 100K per year; thus, you are up 50K per year immediately. Only the economic hurricane has passed, consider rent to own. The low interest rate is meaningless. What matters is that is the home you purchase is going to retain its value.
If you consider home like a car(value going down each year), then, purchase a home. If you want to retain value, I recommend that you rent. In Santa Clara valley, I cannot think of any area that I would purchase now and that includes Saratoga and Palo Altos. It is much economical to rent and wait out the storm. In two years, I believe you will able to afford the much better house at cheaper prices.