I'm in the same boat - was planning on using Parse and no longer think I will. Core issue: complete lack of trust that Facebook won't screw things up as they have so many times in the past (frequent breaking changes to their API, etc.).
Also, complete lack of trust in Facebook due to their lack of understanding of the need for privacy as opposed to pseudo-social ... "stuff".
What's sad to me is I have a HUGELY high view of "you" (i.e. Parse) - your documentation & examples are the best I have seen for any developer services, bar none. I'm just afraid what will happen as you get assimilated into the giant blue monster.
But still - genuine congratulations! You guys have definitely earned it, I'm sure this was the right step financially.
Also, complete lack of trust in Facebook due to their lack of understanding of the need for privacy as opposed to pseudo-social ... "stuff".