Great job getting close to this guy! I think it's great as is.
The only thing I would question would be the blotches of noise on the tail? Also, the BG seems noiser that it should be at ISO 400. You may be able to get better results using Chrominance NR in DPP if this was a RAW conversion.
Once again, the detail, sharpness, comp, and eye contact are all stunning!
Thanks for all the constructive comments. I appreciate them.
I have been experimenting with various PP approaches and I believe I'm getting close to one that I prefer and meets my tastes. Colin mentioned the BG noise. I did apply a different method of NR to this shot and was interested to hear any comments on this aspect.
I've found that DPP is better by at least one stop in the noise department that the previous version of ACR. The version that comes with CS4 looks on par with DPP though. I'm not sure what you're using. Also, the chrominance NR on DPP is great for removing noise but preserving detail.