I like the IS-F's looks. It's over-the-top, but it has the performance credibility to match it's "hey look at me" style. It's a very nice effort from Lexus, a company that normally does make such cars.
To much has been made by the "fake" exhaust. It's there for stylish reasons, let's get over it. Given all the publicity surrounding the exhaust tips and such, I wouldn't be surprised that the upcoming '09/'10 models get a) the same exhaust tips that's fully "functional" or b) switch to a more conventional dual exhaust
If a "fake" exhaust keeps someone from buying the car, then I would venture that they weren't really interested in the car anyways and looked for something to harp on.