WiFi power-saving causes problems with SSH.
Making connections from computer to tablet often fails because the tablet doesn't answer. Doing some network action on the tablet activates WiFi again and you'll get a response.

For SSH and SCP I open a X-Terminal on the N900, gain root, and start pinging my router. Then I can easily access the tablet from my computer without having to turn off power-saving. When I'm done, I stop the pinging.