All i can say is look at the previous Lexus vehicles you've owned and I'm sure you'll see the quality of a vehicle that doesn't break down.Sure any car can have "problems" but a Lexus is built to last.Plus if the warranty is up on any "luxury" vehicle the parts will be cheaper in a Lexus because of Toyota.As far as maintenance you can purchase a plan very similar to BMW where it's maintenence free,just ask the dealer I purchased it and it's worth it!!
Just my 2 cents