Tony,
I am changing the rotors as well so I would not be able to tell you the difference in anything but the brake dust, which should be significantly less. The Braking distance won't change a lot, since it mostly up to the tires, the initial bite will be more powerful in working temp, and the feel and confidence will be a lot better compared to my old original brakes. The big difference should be the time I can drive / use the brakes without having to cool them. I read a lot about the Akebono in other forums, mostly from the US, and they all were very satisfied. I bought them cause I could get them very cheap, 80USD for front set including shipping, while I've been quoted 140AUD for them by the only local distributor.
Mike,
My Is250 had major service (the one that should be done in 90K) in Lexus of Adelaide at 73K, it was time, since the previous owner didn't drive it a lot. I had a minor service (105K) now, while the car only had 85K on it. And yes, they charged me ~490$ :( They wanted to change the brake rotors + pads for ~780$ and I said never!
It should be specified in the log book which service you should have and when. Also Lexus dealer probably knows the best.