I've never been in the United RCC (Terminal 7) but I have been in the AAdmirals club (T4), ReLAX Lounge (TBIT), Alaska Airlines Board Room (T3), and US Airways Club (T1).
• US Airways club is windowless, with the only kosher foods being Milano cookies and fruit. They are pretty strict about outside food.
• Alaska Board Room is on the floor above the gates and it has a nice view of the North side of the airport.
• ReLax Lounge faces West, so can get sunny in the late afternoon. Also, as of April 2011, they were doing construction right outside the lounge (outside the building) so its not very pretty (unless you like construction). There are no views of any runways, but you can see the planes shortly after they take off to the west.
• AAdmirals Club was also nice, with windows to the terminal and the outside, although again, not much kosher food besides fruit (I was there early a.m.)
If you are flying United (T7/8), you can walk above ground to T6 (to access the Continental Lounge) and then underground to T5 (Delta Lounge) without a problem. Total walk time from T7-T5 is about 10 minutes in a semi-crowded airport.