Yes, as I've stated, the 5 is thicker and shorter than the 6. Also, I believe it's a bit heavier.
They're both big knives, but the 5 IMO is just too thick of a knife, where it becomes a jack of all trades kinda knife. But it's not to say it's a not a great knife. Personally, for my uses, the 6 is more advantageous than the 5, since it's slimmer, less weight, and a good sized knife. Slimmer blades help cut through things, while thicker blades help bash through things. I feel the 6 has a good mixture of the two for my personal use. It's not to say that the 5 is worse or anything. Just the 6 suited my uses better. Hell, I was stuck looking at both the 5 and 6 for about a month before I made my decision.
I personally dislike serrated. I get where the concept comes from, but even if I owned it, I'd rarely use it. And I'd much rather prefer using a foldable saw, as it'd make more sense to use, rather than a small serration on a knife.
What do you plan to be using it for? Honestly, on long day hikes, I'll just have my pocket knife since It's compact. Camping, I'll mainly use my Mora. Backpacking, it'll depend on the trip, but my Mora gets more use. I only ask since I sometimes do regret getting the ESEE since it rarely sees use. haha