If the alternative is Downtown LA, (I got news for you, traffic is just as bad) I'll take Long Beach any day. Right by the beach, park, and tons of great food and drink. Last thing we need is another noisy downtown overnight with no outdoor exercise options available other than running from cracked out homeless.
Really, I've almost never encountered bad traffic on (The) 405. Must be the time of day. I think the reason times are padded is because of the traffic at LAX itself. The last half mile can take 30 minutes sometimes.