I fly to LAX on QF Business class and have a connecting flight to Austin out of T4 about 3 hours later.

I fly to LAX on QF Business class and have a connecting flight to Austin out of T4 about 3 hours later. Which lounge is better to wait in - TBIT or T4?

Based upon my recent experience by the time you clear immigration, customs and security you will not have a lot of time to use the lounge.  The lounge in TBIT is streets ahead

If you're QF Platinum you will get the use the Flagship AA lounge which is almost up to Qantas domestic business class lounge standards. I would head straight to T4 as the wait for showers in the AM can be quite long

Thanks for the replies. Sounds like TBIT is a better lounge but given the time and my wait, T4 would be the better option. However, I don't have QF Platinum, only Silver. That means Admirals Clubs?? On the way back I fly out on business on QF operated by AA. Again, T4. I'd have plenty of time at airport. Can I do TBIT? What's the walk like between TBIT and T4? 

About 5 minute walk to T4.. good chance to stretch your legs

Correct me if i am wrong, but you will not be able to access the Admirals Club unless you are gold, platinum or have QC membership.

The only AA business passengers that get lounge access in the US are those flying East/west routes

Lounge access is determined by class of travel on the long-haul flight... even for AA. 

Eg, An AA passenger purely flying business between LAX-Austin would not get access. But an AA passenger flying business between NRT-LAX-Austin, would get access.

Would be lovely for the anonymous mark-down to show themselves muhaha.

Oneworld policy:

Connecting between oneworld marketed and operated flights:

• First and Business Class customers connecting on the same day of travel, or before 6am the following day, can access the lounge when travelling between an international long haul (a oneworld international long haul flight is defined as an international flight marketed and operated by any oneworld carrier with a scheduled flight time longer than 5 hours) and an international short haul or domestic flight (and vice-versa).     
• Lounge access will be determined on the international long haul ticketed flight (either First of Business Class) regardless of the ticketed class of travel on the international short haul or domestic flight.
• You must be prepared to show your boarding pass or itinerary showing travel in First or Business class on the international long haul flight, in order to access the lounge before your international short haul or domestic flight.

Do you need to clear security to check-in at T4, and then clear again to go to TBIT, and again to get back to T4?

Yes - but not the other way (land at T4 you can now go through to TBIT without going through security)

Assuming the OP is flying QF and then AA to Austin, he should have the boarding pass for his AA flight given to him at check in back in Australia.

He can go through customs, drop-bag, clear security at TBIT, use the QF lounge and then go to T4 using the TBIT-T4 walkway connector post security.

Lounge access is determined by class of travel on the long-haul international flight. So even if he was on economy to Austin he would still have access. 

My last time I flew into LAX, I was out of customs and in T4 within an hour. So I would go for the TBIT lounge, unless you turn up at LAX and you have a long wait at customs. 

Make sure your T4 flight is not departing from the Satellite Terminal, and if it is, give yourself an extra 30mins as it requires a bus from T4. 

Yes, i will receive my boarding pass for the AA flight (LAX>Austin) in Sydney. I arrive into LAX at Terminal B. Bag will be checked all the way through. Do I head straight for TBIT lounge? 

You need to collect your bag after passport control but before final customs check... after customs there is a place to drop your bag for your next flight.