As a designer, I was asked last week for my opinion on hillaryclinton.com. Here's my brief writeup.
0) As a programmer, I like the easter egg when you view the source code of the website. Cool ASCII art. Clever advertisement.
1) The modal pop-up annoys the crap out of me. I hate modals. I hope they get rid of it. Even though it only shows up the first time you view the site, it's still really jarring. (View the site in incognito mode if you want to reproduce the pain.)
2) They've chosen a white background and flat design. This has become the modern norm. It's like using Helvetica font: meaning, it's what you do if you're trying not to call attention to the design. It's what you do if you want people to focus on the message and the content.
3) The logo is okay. I can't really make myself see it objectively anymore, since I've seen it so many times. Most of my logo designer friends seem to like it.