I think some other guys experienced the CTDs too. At least that's what I understood from their posts. I'm also in that club although my main problem is to grab the nature of the beast. From what I can tell, it's not a single key press or operation which seems to cause problems, it's more like filling the PDCS with data and actually working with the modes leads to e.g. a CTD.

I even had a BSOD lately and I can tell you that I haven't had those things on my machine for a long, long time. So I'm sort of cautious now when it comes to the PDCS and I think that 'oh, lets not press too many buttons' attitude is what I've read in the posts of others.

I wouldn't call it unusable since it actually does compute things and doesn't blow up the PC on the first key press, but I wouldn't call it stable in the current state. So I agree, receiving a CTD or worse when actually using the PDCS isn't what a sim flyer is dreaming about. Ending a flight in mid-air with a CTD because you wanted to look up the go-around EPR surely isn't fun and much worse than 'just' some wrong values.

Did you discover some pattern to trigger a CTD yet?