Comparison

Aumont is 5 inches taller and throws harder.  Its not that surprising that he's projected to go significantly higher.  The separating point when it comes to HS pitchers in this draft (and most drafts) is projectability and potential.  You mentioned Aumont, but how about Bumgarner(sp)?  From what I've read he only recently started throwing breaking balls and is a huge project, but because he's a 6'5 lefty (with a projectable frame) and a fastball that sits in the mid 90's he's projected to go higher than several more polished HS pitchers.

Aumont's arm action is more compact, but his arm slot will make it more difficult for him to throw strikes and a consistent breaking pitch.

Griffith's action is pretty long, but he doesnt seem to have any problems repeating his delivery and is very athletic. I think he's good enough to go in the 21-30 range and should be a very good pick in the supplemental round.

I've been a fan of Griffith since I saw that youtube video of him facing Burgess back in April or so.
He has good mechanics and has big time heat.  His breaking ball has the potential to be a dominant pitch.

I'd be happy if the Cardinals took him at 36.

...Griffith looks better b/c he is more polished, but Aumont is said to have a big upside. He obviously throws hard, but his delivery and pitches are all over the place in that video.

I'm not an expert in pitching mechanics by any means, but these are my observations:

Like several other tall pithers in this draft including Brackman, Beavan Bumgarner and even Porcello, Aumont largely negates his height advantage with a  low arm angle.  Watch Aumont.  He never gets his hand above his ear.  The other thing I notice about him that is similar to the other pitchers I mentioned is he never extends his arm.  He just brings his hand back behind his ear and then kind of slings the ball.  Does that protect his shoulder, or does it compensate for a weak shoulder?  Of all of the great HOF caliber pitchers I can think of, only RJ slings the ball like that.  Everyone else is over-the-top.  I guess RJ proves that it can be done, but is he just a freak of nature?

Over-the-top deliveries give a better dowward plane to the fastball and allow for better downward break on the curve and slider.  Also, alternative secondary pitches like the splitter and knuckle curve almost have to be delivered from over-the-top.

Griffith appears to be basically stronger, more athletic.  He has a higher arm slot.  He gets fantastic extension.  I'm picking up from other comments that he might need some work on using his legs and meshing his leg work with his delivery, but that seems a lot more teachable to me than completely reworking Aumont's arm slot.  Again, I wonder if Griffith's extension and arm slot signify a stronger shoulder or does it expose his shoulder to injury?  If an over-the-top delivery is riskier for the shoulder, how come so many HOF caliber pitchers with long careers use it and not get injured?

In short, I love what I see of Nevin Griffith and would be ecstatic if the Giants took him late first or early supplemental round.

agree with DrBGiantsfan i too would be estatic if the Giants took him in the supplemental or even as high as #22 I like him a whole lot well i guess the cats out of the bag becuase thats who I was going to take with the angels oh well.

I like Griffith more than Aumont, and I like him as well as a few of the other highly thought of guys, so personally I would consider Griffith underrated.  
Aumont may also be overrated though, this trend by the scouts to find guys that are 8ft tall and think that means they have unlimited upside is dumb.  
There are alot more "short" dominant pitchers in MLB than there are 6"7 NBA small forward types.  This new obsession with height is so over valued, it makes no sense.  Take Brackman as another example, if he was 6"2 he wouldn't even sniff the top half of the first round this year, maybe not even round 1.  But say 6"10 and the scouts start falling all over themselves.  

for blowing the cover off the guy I want the Mets to take at 42!

I've been trumpeting Griffith for a little while now. Love his delivery, he already has a ton of poise and mound presence, and he's still projectable.

Once he breaks his hands he really reaches back in a similar manner to Jered Weaver.  This causes more stress on the bicep and has caused Weaver biceps tendonitis repeatedly over the years.  Aumont doesn't maximize his physical tools but I still prefer him to Griffin.

Intuitively I like Aumont over Griffith.  Aumont looks more compact in his delivery and releases at a higher percentage of his stride length.  I think he has a delivery that with some minor work can be repeatable.  Griffith looks extrememly raw to me with a dead front side.    His glove actually never gets above his waist in several deliveries causing him to release earlier than I would like.  He has alot going which to me signals a guy that will have trouble repeating his delivery, although he does appear athletic.

Aumont's fastball movement was noticeable in the video, Griffith I didn't see at all.  Aumont was not consistent with his breaking ball on the couple they show, but he did flash a pretty tight one early in the video.  Griffith's was an early breaker.  Not that this can't be tightened up but I think Aumont's breaking ball is ahead of Griffith's at this point.

Personally, I think too many people focus on arm action and arm angle at release.  The last ditch adjustment mechanically is to start screwing with arm slot and release point.  I would certainly not sacrifice the obvious movement Aumont has to get his arm up to "take advantage of his heighth".  

Aumont appears to be much more intimidating than Griffith. As smooth as Griffith's delivery is, I can see a batter digging in against him whereas the same hitter might be worried about his personal safety when facing Aumont.