Meh, I'm on the other side of the fence on this. Nice, but I wouldn't use it.
I guess I'm old-school and prefer writing in a laboratory notebook. I can pick up a 100-page graph paper composition notebook from Target or Office Depot for < $2. I can write in it with a ballpoint pen, tape reference material and photos, emails, etc onto the pages, and carry it around with me. I can quickly page through it and find exactly what I'm looking for in a very short amount of time. It's a permanent record and can be "officially" witnessed by other scientists, which gives it more clout if it came down to a patent issue in court.
I've attempted to do something like this with Evernote but it became very hard to deal with when I needed information from it. I had to be at a computer to use it. Text search didn't always work and I got really tired of having to click through each page to find information I was looking for in it...