Yes Lightroom 3.6 noise reduction is quite good but not great. You can get better results with dedicated software. I've read a number of reviews of various software packages and plugins but there is only one I personally use: NIK Dfine 2.2
I fond it to be FAR beter then Lightroom and NIK is also available for Aperture. How it works in Lightroom is that you have to select your image then right-click and choose edit in NIK Dfine. This opens your image in the plugin application where you work on the noise reduction. Once your work is completed, your image is added into the Lighroom library. You can choose to edit the original or a copy of the image with adjustments. The plugin is not seamlessly integrated within the application framework as the work "plug-in" would sugest but it is not very cumbersome to use. Personally, i use Lightroom tools for most of my work and only use specialized plugins such as this one for selected photos.
After your noise reduction is complete I would also suggest to use more advanced sharpenning utility. Again, I use a NIK plugin Sharpener Pro 3.0 for the occasional photo i deem worthy.