Welcome. Did you make the right choice? Can't say >
without knowing what you have owned and what your expectations are for the IS-F? If you are planning to tow your horse trailer with it, it may be the wrong vechicle for you. If you think you are going to get 40MPG with it, again it's the wrong car for you....
Is the IS-F a fantastic sport sedan? YES, IMHO it is. Can it compete with the BMW M3, MB C 6.3AMG, Audi RS4, and the likes? Again IMHO yes. If you are looking for something that can be tame, well manored, provide a high level of comfort and conveniences while also being able to perfom at the highest levels of a sport sedan, you've made a great choice.
Though I've only had my IS-F since the end of January and only have about 3000 miles on it, the more I drive it and learn about the car as I drive it, the more I appreciate all of the subtle touches and performance features of the car. I think for most, the IS-F is more car then they could ever want or need. And for the rest of us it keeps a smile on our faces ever time we drive it or even think about it.... So again, if that's what you are looking for you've made a great choice....