[...] Each class has it's own chapter that details different builds and lists the powers available (Between 3-8 per level it seemed). Monster entries are much shorter than in 3.5, but much more concise. [...]
The books look and feel great, there seems to be more artwork and a more logical layout in all the 4e books. The new DM screen is 100% better than the old one.[...]
Ok, multiclassing is done entirely through feats. You take one feat to multiclass and gain a power from that class, and then take additional feats to take more powers from the class.
Rituals are obtained by buying ritual scrolls or ritual books. Ritual scrolls are consumed after one use, books teach the ritual to you permanantly. All rituals seem to have a casting time of at least 10 minutes, require a material component, and require the use of the ritual casting feat (which wizards and clerics get for free at 1st level) Most of the divination spells in 3.5 are now rituals as well as some of the old illusion spells.
Each class has about 15 or so pages written about it which includes powers and paragon paths. It's possible to make characters that don't fall into their presupposed role, but you have to multiclass to do it (you'll need defender powers from fighter to be an effective rogue defender, etc.)
There are no subrace rules (drow, gold dwarf, etc.) in the PHB.
There are approximately 3 times the amount of feats in the 4e PHB as the 3.5 PHB.
The DMG is all about how to run a game. There is no reason at all for a player to have one.
Oh and by the way, Greyhawk, Ravenloft and Dark Sun are definately getting 4e campaigns down the line as well as Planescape and Spelljammer (which they just started working out). They assured us that we can look forward to most of the old campaign setting being remade, and mentioned the above by name.
