Overall, the game played pretty much the same as 5th ed, but with a dozen minor changes. We played a mission called the Scouring which involves 6 objectives being placed on the table. However, not all the objectives are worth the same amount and you dont find out until after deployment what they are worth. The game was played short edge to short edge, with a 24" no-man's land in the middle. This was all pretty cool. We didn't bother with the rules for random terrain, but we did use the special objectives rules, which seemed pretty superfluous to the actual game, but didn't cause any major upsets.
The Warlord special rule was likewise not a big game changer, but I could see how it might be in specific situations.
The way vehicles work has changed quite a bit, I killed a squadron of 3 Warwalkers with nothing but glancing hits, whilst Ikeda-san got a penetrating hit on my Predator, but only succeeded in killing a twin linked bolter.
Wound allocation wasn't too big a problem, though at times it was tricky to determine which model was the closest. Mixed save units slowed the game down a bit (Phoenix Lord 2+, Exarch 3+ and Aspect Warriors 4+ in one unit for example), but in single save units, made no real difference overall.
The changes to the assault phase were noticeable. My Berserkers failed a 6" charge and took casualties from snap fire, which I wasn't too happy about
The game ended with Ikeda-san losing, but having come home and checked through my Eldar codex, I think his army list was short by at least 300 points.....
Anyway, it looks like the changes in the new edition will take some getting used to, but it should still be just as much fun to play as 5th.