well, as far as I'm concerned, I don't think that ProPilot is a fun experience the way Bruno says it is, but that doesn't mean that I think it's bad...
Propilot is not fun. It is hard, it is stressful occasianally, and it can be a right pain, but the whole point of propilot is, is that it's a challenge. Sometimes, I feel like I would like to be marked, because it gives you a chance to see how good a pilot you may be, and it makes me feel very good about myself if I get 0. I get the impression that alot of people get stressed if they get a penalty, and there was plenty of times in the UNHCR when I got annoyed because I got a penalty, and didn't even realize what I did wrong, so if you're descending, and you overspeed, it's your fault, for not being aware of what's going on.
non-PP is what you need to relax. If you fly with propilot when you want to relax, it's like having to multiply with a headache. Don't do it. I only fly ProPilot if I feel up to it, otherwise, I fly non-PP.
as for these random mistakes, I have never even had one before, but I have crashed a plane on PP, but (I don't mean to sound offensive in anyway) I don't think about the crash. So what? I've now got a high FAC. Doesn't neccessarily mean I'm a bad pilot. I've done 71 successful flights, and one event I happen to break down while using PP. Does it really matter?
Although, I have experienced bugs within propilot, like I got a rating of 1100, yet I really should have gotten 110 and I don't know what happened there but when you fly PP, I think you need to expect that things may go wrong, and you need to be in a mood to not get mad at it.