Read around the forums the dealer vs independent mechanic debate has been discussed many times. My stance on it is that there is nothing exotic about a Lexus, its not a Ferrari or a BMW. This is a GOOD thing, meaning anyone really can work on it. Companies like Audi, BMW, VW shut out the independent guys by designing complicated diagnostic systems that require equipment so expensive that independent shops simply can't afford it. Lexus doesn't do this. Lexus DEALERS capitalize on owners preconcieved notion that their new luxury automobile is a marvel of complexity that only the dealer can make heads or tails of. Thats why they get away with the rediculous labor rates (some dealers charge up to $120 an hour, more than some medical doctors) and as wwest mentioned the rediculous maintenance schedule (dealers ALWAYS go by the severe maintenance schedule, if you dont deliver pizzas or do high speed road chases routinely, this is overkill). Fact is, the Lexus is proof that a great automobile doesnt have to be as complex as a fighter jet.
This means, that if you dont need to take full advatage of things like the free loaner and pickup and dropoff, then you need not take it to the dealer. Find a good independent shop you can trust.