What are some reliable luxury car brands? Is Lexus the king in that category?

yes, by far. My wife drives one, says it all (but I am still cheap and got one for 4 grand with 60 thousand miles on it from a customer's dead father's estate.)

The pricing on luxury cars doesn't make sense to me. One would assume when paying $40k + for a Mercedes or BMW you would get advanced driving machine that is reliable(since its sophisticated technology).