Here's an anecdote of a type 1. I thought it only helped type 2:
RS is a PREbiotic (feeds gut flora). It is not digestible. (unless you heat it)
I am borderline prediabetic (T2 of course). I started out being reactive hypo in 2005. A year ago my A1c started creeping up (to 6.0), so I started using a BG meter and low-carbing. Got my A1c down to 5.3, but my starch tolerance was very poor.
In December I started RS. It has improved my starch tolerance tremendously. It helped my FBG (99 to 85) and 2 hour post prandial BG (120 to 90). After starting inulin (another prebiotic), and taking some soil based probiotics, my 1 hr post prandial is starting to improve too (156 to 109 after a 4oz potato).
RS feeds gut flora which seems to play a big role in BG regulation (think incretins, for example):
There are several type 2 RS anecdotes if you follow the links in the first link.
I urge you guys to try it on yourselves and see. Start with tiny amounts and work up slowly. The most common (temporary) side effect is hilarious amounts of gas.