I'm using Raspbian (2014-01-07) on a model B and I'm experiencing the same problems as many other users: network connection is lost as soon as I do anything that creates more network load than "ping". I even can't run "apt-upgrade" without loosing network.
I tried "dwc_otg.speed=1" in cmdline.txt. With this, the Pi's network does indeed run very stable! I haven't had a single loss of connection since I set this parameter, no matter what stress I put on the network.
But, and here comes the well known downside of this solution, it breaks the use of mouse and keyboard!
So, for now, I have the choice between two evils: loosing network nearly as soon as I start to use the network, or not being able to use a keyboard. This situation is very unsatisfying, annoying and frustrating.
Apart from tossing the Pi in the trash and buying some other mini computer that will suite my needs: what can I do to have both network and keyboard/mouse?
Would another distribution be a solution? Is this a Raspbian-ony problem?