Well, I am certainly no expert on Hill-style bows. I've only had my Shelton for a few days, and it is the first straight grip bow I've had since the little lemon wood recurve I got when I was 8 years old. I can make some observations, however.
I have been shooting my other bows with a grip much like Rob describes with some success. When I got the Shelton, I first tried the low wrist "Howard Hill" grip. Then I experimented with the "Rob DeStefano" grip that I had been using.
For me and my bow, the Hill grip just works a lot better. I am much more consistent and groups are much smaller. I have also noticed that the bow is WAY quieter when using the low wrist grip. Don't ask me why, it just is. Old habits die hard, so I still catch myself raising my palm at times. I usually hear it first, but my shots also seem to wander off target a bit. The bow is pretty forgiving, so the hits aren't way off...just off.
When I use the Howard Hill form, this bow is almost magical. The arrows seem to guide themselves to the center of the target, no matter if it is 10, 15 or 20 yards. I haven't tried much longer ranges as I am still tweaking and tuning. This morning I reserved my string as the serving that came on the string was too fat for my nocks. I also experimented with nock point below the arrow nock. Much to my surprise, it is easier to nock an arrow from a back quiver that way. I'm not sure it made a great difference in terms of accuracy, but it didn't hurt it either.
I'm not saying Rob is wrong. I'm just saying it looks like, for me, the low wrist grip is going to work better. Don't be afraid to experiment until you find what works for YOU.