Hey J R,
This is definitely a loaded question. I'll bite though. Tableau 10 makes great improvements in the look and feel of dashboards in Tableau. I, personally, am a huge fan of the new styles.
That being said, they are preset. You can do tons and tons of formatting, but there are certain things you just cannot do without using outside imagery.
Can you control every pixel of the screen? No. Can you control a good majority of the formating? Sure!
Yes, Derrick...definitely a loaded question. I purposely left it somewhat generic. Your response is precisely what I was looking for though. I haven't personally used Tableau 10 (T10) yet; however, my intuition suggested that it's not able to produce pixel-perfect output, even with all the new formatting options. And, this makes sense...most data viz/discovery tools are not purpose-built to produce production quality enterprise-grade reporting (other ancillary tools in some stacks serve this purpose though). Frankly, I think the term "pixel-perfect" is a somewhat overused marketing term that has very narrow use cases - at least, within a BI context. But alas, I was asked to evaluate this feature across specific tools that align with our requirements.
Again, thanks for your response.