My blog ran for a little less than a day with this plugin installed, then just broke completely. Wouldn't load a page at all. I have 3.2.1 installed and the latest plugin. It is a real shame because I really JSON and this by all accounts seems to be the best/only way to pull custom fields into JSON.
Will be really excited when the bug is worked out.
And, no, I didn't install anything else, no traffic spikes or anything, I am 100% sure this was the problem.