Ran this last night with my regular 3.5E grp when a member was out of town.
Heres how it went. Started the night off with 4 players, the warlock, ranger, wizard, and cleric. The first room was ok, but i had to constantly tell my players not to go crazy with their dailys on minions. They dealt with the minions and the lone initial skirmisher didnt have much of chance when the minions fell quickly. But they were able to do some dmg to them and give the players a good feel for 4e combat. Then I had the other 2 skirmishers arrive just as the 4 other minions came out, and the combat advantage started to come into play. My players were very hesitant to move around, still in the 3.5e mindset. So the ranger took massive damage from the skirmishers spears. But patched up with surges after the encounter they choose not to follow the path of the one skirmisher that fled, but rather hop the stream and follow the norther most path.
Where they found an overturned table and the hobgoblins. Initially I had all 4, the two archers, the soldier, and the warcaster in, but it soon became apparent the party was in dire straights. The fighter was just destroying their front line, they were all stuck in the small causeway, the archers were consistently hitting people for massive dmg, and the warcaster, my god his dmg output was incredible. Needless to say, even after 1 of the archers "fled" to give them some breathing room, the party wiped (wizard ran) without downing a single hobgoblin.
So we reset, I used the same encounter stats, they used all 6 chars, and I just plopped them on some random road with a barricade. With 6 this fight was still tough, but it was spread out enough in terms of damage to let them really see 4e combat. The fight still took a surprisingly long time, but it was a little better on their end for rolling. Although the look on the wizards face as he thought he got the jump on the warcaster was priceless, as I had the warcaster smash him in the face with his lightning rod.
After this encounter I just reverted back to the adventure and ran nightscale as is. Wow. 4e Dragons can be tough bastards. First of all, dragons are not impossible. They are tough, but they can be killed. The dragon encounter would have literally lasted 4 hours by itself, I stopped it at about 1.5hrs. Maybe when things pick up and we know the rules, but my players were quick about actions, its just the dragon is tough to hit and takes so little dmg compared to its massive 280hp. Dragons seem to have 1 or 2 key abilities, but when expended the combat becomes repetitive. This dragon would've prolly dealt enough dmg to hurt them before they could fell it, but the rounds became the same. breath, darkness, dbl claw,breath,darkness,dbl claw, rinse repeat. Granted the dragon wasnt doing massive dmg with any attacks, but it would wear them down. I suppose its to be expected, the encounter is a "boss" encounter and prolly not appropriate for 6 1st lvl chars to consistently "defeat". But it was fun and my players really like how dragons will be in this edition.
Time also seemed to fly, and where the increased dmg dealt by both players and monsters might make you think combat is quick, its not. With second winds, cleric surges, and pally's lay on hands, the battle can keep going against the massive HP of the mobs.
This edition finally feels right. I no longer will have to look at my players faces of disgust at lvl10 when I throw some orcs at them. I will no longer have pain when I have to design 15 10th lvl orcs either. It seems the monsters will scale appropriately and with little effort. While the kobolds might have been a joke, they were no where near the joke they are in 3.5e. And the hobgoblins might have given my players nightmares.