I've had Kaiser for the past 5 years and delivered my baby girl at West LA in '09. I was nervous about the switch, too. Thankfully, I'm pretty healthy and rarely need to see a doctor, but all of my experiences have been positive. And if you know the system you can minimize some of the challenges other patients have.
All of the doctors are on email. Some are better about responding than others, but you can get so many questions answered this way and save both you and the doctor a lot of time. Also, you can manage appointments, see test results, get a summary of your last appt, etc. online.
While their schedules are usually set weeks/months in advance, you can always ask your doctor (by email) or call the nurses stations to see if they can squeeze you in when it's really urgent. Same day appts are with other doctors in the group are available, as well.
Book your appointments first thing in the morning or right after lunch to avoid long waits. Parking at West LA can be tough. Plan to arrive early. My doctor has a no tolerance policy on tardiness.
Your primary doctor will have to give you a referral if you need to see a specialist. If you can get an appointment right away, ask about cancellations.
In terms of technology, they seem way ahead of other providers. I love that all of my records are accessible to each and every doctor I see. I don't have to worry about requesting copies and making sure they get where they need to be. My mom is 65 and I wish she would go with Kaiser. I just worry about keeping all of her doctors, records, meds straight when she gets older.