OP here. This maintenance package covers all the scheduled services up to 50K/4 years as recommended by Lexus in the owner's guide. It does not cover wear and tear items such as brake pads but the air filter and cabin filter is covered.
I try to take my cars to independent mechanics but the service seems to be always a hit or a miss. This being my first Lexus I am leaning towards taking my RX to the dealer for all the scheduled services. Hence I am trying to price this package and compare it to the expenses I would have paid the dealer if I had done pay-as-you-go for all the scheduled services up to 50K. If it is a significant savings by prepaying, then I may as well buy it now. I don't have any hard numbers what would be the dealer charges for pay-as-you-go services upto 50K for a RX, but looking at SW03ES's numbers, it seems like a good savings by going with the prepaid package.
I am a frugal and pretty hands on guy. I have changed oil on my cars, even replaced a transmission gear sensor, and exchanged tranmission oil on my Honda Odyssey, but due to family committments, I am not very prompt on the service schedule. Another incentive by prepaying I will be more committed to keeping up with the scheduled service.
I am not overly concerned with the dealer going out-of-business in the 4-year timeframe. Anything is possible, there are no guarantees in life; unfortunately if it happens, so be it so and move on.