From what I've seen of Ennis, this is kind of the gist I got compared to MCW:
Ennis is in no way the passer that MCW is. MCW sees the floor in a way that very few players in the country do. He probably had the best court vision in the country this year. (This doesn't mean Ennis isn't a good passer, because he is; but MCW is a very special passer)
Ennis has a tighter handle on the ball (like Triche), and he's a pretty good passer and an average shooter (which is obviously a step up from MCW this year), but he's nothing special in terms of shooting ability.
The thing that I love about Ennis is that he just looks like a floor general out there. He knows when to push tempo, knows when to slow it down, knows when to attack and when to get players involved, etc.
Having said that, MCW looked like he was in control in high school as well, while looking like a far better scorer and passer, so we'll see.
I think one of the things that hurt MCW pretty badly at Syracuse is his skinny frame. In high school, he handled the ball very well because people in high school weren't substantially stronger than he was. However, in college, he was easily bumped off the ball, so he wasn't able to control the ball as well as someone with his talents should. Ennis doesn't have that issue, as you can tell by looking at him that he has a sturdy frame, so in that sense, I think ball security will be less of an issue with Ennis.
I think Ennis will be another very good PG for us, and by the time he's done here, he could be a more consistent player than MCW was for sure, but MCW is a more talented player by a decent margin IMO. If he puts it all together, I think he'll be the best PG in this year's draft.