In January I did MEL-YVR with a Californian drive thrown in. The Trump-Wall-Public servant issues settled 2 days before we came home. Here's how the various airports compared:
Arrive LAX one and half hour queue at Customs. No wait for bags. Further 90 minutes before keys in ignition of rental car (Dollar)
Drive to SFO. Excellent rental car drop-off experience. 15 minutes through security (nb private security contractors). UA to YVR, left an hour late and couldn't seat me near my 13 year old son. No lounge access as SA.
Arrive YVR mid-afternoon zero wait at customs! About 20 minutes for bags. Key in ignition of rental car 10 minutes later (Avis).
Rental car drop-off Whistler very easy, lovely staff, later in the day I realised I had lost a CC and they drove me back to Creekside to look for it, before returning me to hotel.
Bus Whistler to YVR, rental car pickup a piece of cake again (Alamo). Drive YVR to Bellingham (USA) 90 minute queue in car then 30 minutes interview with customs at border. Painful....
Drive Boeing factory to SEATAC, I-5 a carpark because of crash, but we got there in time. Rental drop-off excellent. Security at SEATAC 5 minutes. Alaskan Lounge pretty good, son filled up! Alaskan Flight to LAX perfect. Arrive Terminal 6 underground connector to T4 then new connector from T4 to TBIT. Ski boots and bags getting heavy by now and moving walkways not operating.
Arrive QF First lounge and settle into the salt and pepper squid followed by minute steak. Two hour wait for shower (13 year old a bit on the nose by now)! Old QF A380, noisy in PE and pretty average service, dirty toilets etc. Arrive MEL passport control and customs pretty good but how is it that it always seem to take a hour of waiting for bags.
So, the bad - Customs LAX, rental car pick-up LAX, Canada/US border cross (by road), and bag wait at MEL