I believe the program you are referring to is the CALHFA ofen referred to as a Cahfa loan. This program can be combined with the CHDAP California Housing Down Payment Assistance Program.
I believe if you google NEHIMiah you will find that the Nehimiah program might have been diwscontinued as it was circumventing different procedures and was not that adventageous for the buyers. You can form your own opinion.
These programs have income limitation, and housing price limits. The negative as I see it right now is taht if you ahve excellent credit there could be lower costing loans available but if the downpayment is the challenge this might be the only way to go.
The other negative as I see it is that there is a 1.5 origination fee with these loans. I have not called any lenders on this but I would think that a lender might be willing to discount a portion of that origination fee.