Hello [MENTION=812526]mirfip16[/MENTION],

A couple of comments.

Which lounge is better is probably best discussed in the Lounges at LAX - Access, Showers, Questions, Which One? [Consolidated thread]. United has a brand new club at LAX, you can read reviews here: LAX T7 United Club (UC) -- Reviews, Experiences, Q&A, .. Club/lounge access rules and questions are best answered in the individual airline forums.

Secondly, the US does not have exit passport controls. TBIT is used for domestic and international flights. You will not have to pass through immigration and customs when entering or exiting TBIT solely for the purpose of using a lounge (that pleasure is reserved for passengers arriving on international flights).