My Campaign, which started at 1, is now at level 26. (we are playing thru the H1-E3 series from WOTC..halfway thru E2 right now).
Play did seem to bog down when we got to epic some. Fights took longer and the PC's seemed to not be terribly threatened (at least from my perspective as a DM).
Then about level 24, I blanketed reduced HP's of monsters by 25% and increased their damage by 1 or 2 dice (usually only 1die, but if a power only did 1die damage--especially at-wills--I increased it by 2dice). So far, thru about 10 encounters since the change, the fights are shorter, but more intense. The party is still winning, but they seem Threatened by the fights now.
Other than that, it runs pretty much as heroic and paragon levels.
My party:
1/2 elf Paladin of Kelmvor
1/2 elf Ranger (greatbow)
human Cleric
Human wizard
Tiefling infernal warlock
Dragonborn ranger (beastmaster)
With the radiant damage this party puts out, the multitude of Undead they seem to be fighting die quickly
