If you are running a PC with a high resolution screen (pretty much any high end laptop these days for example), you'll have experienced the issue where the scaling of text, images and icons in the Notes and Designer clients is awful to the point of being unusable.
Dan Anonielli has come up with a solution which seems to work very well for me at least: http://www.danantonielli.com/adobe-app-scaling-on-high-dpi-displays-fix/
The basic idea is that when an application launches, Windows asks it if it is high DPI aware. Notes (well Eclipse), claims that it is and so Windows believes it and we get the resulting mess. But with the new registry entry mentioned in the blog above, we tell Windows to first look for an external manifest file that can override this default. So we can tell Windows that Notes is not high DPI aware and so Windows handles the scaling for us.
It's not a perfect solution, but until Eclipse / IBM come up with something better then it's a good fix.
Edit 23rd May 2016: I had cause to come and revisit this issue thanks to a customer and found that the solution above didn't always work and I couldn't find the reason. However, if you install 9.0.1 FP4 or higher then you should find that things are a lot better than they were. Still not perfect, but usable at least.