IMO we havn't really seen enough of either Delton or Skylar to really say which is better, other than 'first impression' quality opinions.
Both have played well in general and, were it not for the coaching staff putting Ertz back in at the end of the Texas game, it's entirely likely that both would have put together come back wins, although that's pure speculation of course.
As it stands now, Skylar at least seems to have a bit more presence in the pocket and he also makes it look a lot easier.
Delton tends to look like how I'd feel if 'I' were the one out there (that is to say, looking occasionally lost, stressed to eff out and wondering who to hell thought it was a good idea to put me in).
Delton has less eligibility but can be an excellent runner, although his physical limitations clearly impact his passing ability. He clearly makes a good #2. Skylar has more eligibility and his passes don't look like skeet flying out there to be picked off but not as good of a runner. I'd prefer personally to see him the starter unless/until Ertz comes back.
But what do I know, I'm a loudmouthed idiot. I'm just happy to see a come back win, and in a game I really didn't expect to see any type of win.