Hield or Murray? You take the 19 year old any day of the week.
No, you take the better talent. Taking guys purely due to their age is generally a poor decision - if you need an example just look to James Young, who Murray happens to look quite a lot like right now.
Age is pretty much the ONLY thing Murray has over Hield right now. Murray's greatest asset is his outside shot, and Hield's outside shot is better. Murray does have better PG skills, but his PG skills are still medicore (less than 1 assist-per-turnover and average ball handling) so that's kind of a moot point.
Hield is the safer pick, and he also has (IMHO) a higher upside as well - despite his age. If you
want James Young 2.0 or Jimmer Fredette 2.0 then by all means, take Murray at #3.
Dunn is also a better prospect then Murray, but I put him after Hield because we need size and outside shooting rather than PG skills right now, and Hield is bigger then Dunn and a better outside shooter.
But if we didn't get Hield, I'd want it to be Dunn.
My problem is that I basically agree with you 100%, cs

I also think it's between Hield and Dunn (excluding Bender, because I can't evaluate him). The problem I have is that neither of them should be picked by us at #3.
There's a lot to like about Hield, but if he doesn't work out, Ainge will look like an absolute fool. I can already hear some guys sharpening their knives in the corner. The thing is, in that case, they would have a point.
Dunn is the most NBA-ready prospect I have seen in years. There's absolutely zero doubt in my mind that he will be an NBA player, but he's also pretty redundant to what we already have on the team. So if you want to draft Dunn, you kinda have to trade one of the guys who play in our backcourt right now. That's not really improving our situation, and thus would be a very underwhelming outcome for a #3 pick.