I will try and make this very brief having used AS Board Rooms many, many times in the past, along with having a friend that works for AS, whom I stay with several times a year in Seattle.
If you are on a paid F class fare, you have access regardless of it being an AS or AA flight number in the booking. The printed boarding pass you will get will have the AS flight number on it with the fare bucket next to it if on AS print stock or in the class field on the right panel or main highlighted area of AA print stock (looking at all 12 boarding passes this year from SEA sectors on AS)
QC members will only get access if you are flying on a QF code share flight, whilst this will not always show on the boarding pass, it is in the system so you should have no issues.
The AS day pass system is great for those without access or status to get in to the BR, cheaper than what AA or other airlines ask, and the lounges are IMO much better than what AA offer (with the exception of Flagship lounges for WP's etc).
The LAX BR is comfortable, they always have assorted snacks, crackers, cheese, fruit, cookies etc, and later in the day soup or chilli is on offer. They have a wide range of beverage choices and it is not serve yourself alcohol as has been mentioned, you need to ask customer service staff during the day, or the bar staff in the evening. 3 alcoholic beverages is the published limit, but I have never had issues on longer stays having many more than this, just be courteous and a tip here or there does not go astray.
The SFO BR is quite small (smaller than the AC at SFO) however they do have slightly more on offer in regards to snacks than the pretzel mix in the AC. I always get my fair share of crackers and Tillamook cheeses along with some carrots or celery and ranch dip. Alcoholic beverages need to be ordered through the front counter staff or if someone is lurking in the back room near where the used plates and cups are left. The one strange thing with this club is all sodas are kept at room temperature in the right end cupboard below the snacks and coffee machine, just add ice and all is ok (oh, btw, the Jones sodas they stock in the BR's and inflight are excellent, especially the Root Beer). There is free wifi access, just look at the cards on various tables etc for the login details.
Last but not least. the SEA BR is one of my favourite lounges. I always love waiting in there for an early morning flight in winter with the fireplace going (well, gas fireplace anyway) a flavoured coffee and pastry. You can sit downstairs where there is plenty of desk space to get work done. or go upstairs and watch some TV.
HTH, I just got back from there 2 days ago and will be back flying AS in 18 days time, hopefully it will be a white xmas, although so far Seattle has just had loads of rain with some frost in the past few days. (nothing like last year, with 2 foot of snow on the ground at SEA-TAC and more in higher elevations in metro Seattle/Tacoma)
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