Not to derail the thread - but I've never played 4e, only watched my friends playa couple sessions before they went to PF. The one common comment made about 4e as people went up on level was the extremely long combat times due to the various daily powers and tactical nature of the fights with numerous comments saying 6 hours for some fights. When you mention streamline in 4e, what are you referring to and you or others can PM if you'd like and I'd appreciate it either way.
In my experience, 4E combats can last 2 hours or so. I would guess a lot of them last 90 minutes, depending on the setup. I have never played a combat that lasted 6 hours, so I cannot say anything about it. There are 6 PCs in the group I play with. When we played with only 4 PCs combats did not last that long, I would guess 60 minutes maybe?
What the 4E group really likes is the fact that there are dailies and powers that let you do extraordinary things to begin with (meaning at level 1). Our combats tend to be precisely about where one PC or enemy stands, if PC 1 is close enough to PC 2 to take full advantage of powers etc. And this is combined with roleplaying combats, too. So, for instance if the Psion is standing too far away from the Paladin, that player will be reminded on a roleplaying level and the tactical discussion is conducted on a roleplaying level as well. At least most of the time.
Regarding the streamlined nature of the system:
As a DM you know what to do and the system takes you by the hand. There are tables with numbers from which you can easily build encounters, make your own monsters or construct a skill challenge. The system is streamlined enough that you can, for example, easily refluff an existing level 17 opponent into something with an entirely different flair, because the mechanics are sound.
As a player, all PCs have the same setup. The roles make it easy to understand what your character should and will be able to do. The math is pretty clear while the powers, magic items, you name it, can be refluffed quite easily. The chassis of at-will, encounter and daily powers are good as every class can enjoy them. The players also love the magic item list that will provide their PCs with useful items they can count on. As a player I have always disliked the fact that in the 80s my fighter had to switch from broadsword to axe just because the "module" provided an axe +2 but not a flaming broadsword +1 (which I would have liked much better because flames on a sword are much cooler). We are glad these days are over.
