In a game I recently had with a fellow the following ocurred:
my webway opened
next turn, guys swarmed out and filled all available pace around the portal; such that there was no available space around the portal
opponent tryed to kill them (saing that the raiders count as having mover 6", no more, so they can be penetrated), failed, too bloody many of them
next turn: OOP!!! no space for reserves, opponent argues, no available space, no guys come in, my guys cannot come in!! [argue argue.. read mini rule book, not clear enough.. read big book,, exactly the same]

from the way the rules are written, it seems that they have left out that wonderful little bit about how far models count as having moved when they come on. In 3rd ed it was 6", but with no numerical value, do they count as having mover (also unclear in rules), can they move (hey, pop in and CHARGE), do my raiders count as glancing hits only, and... can more of my troops come in, if there is no space around the gate (if no, a one turn gap occures between filling all space around the webway)?

the result of my opponents nitpicking was that my troops that came in from the portal could move, shoot,and charge; but my raidrs could be penetrated.

So what is correct? What is Reserves in 4th ED, and why oh why can't GW make the rules at least somewhat clearer (I like the flexibility and all, but common, how much is too much)???

another thought, real quick, you can charge the turn you come on, right?