I have been in the quantified self mode last month. As part of that, I began tracking my nutritional intake daily. This started by method of pen and paper. This though became unbearable so I began to consider the alternatives solutions.
Also known as MFP around the web seems to be the most popular nutritional tracker in both the web and mobile space. One of the bigger issues with it that I have found is that any member can submit foods. This forces a user to sift through the food to ensure the item they added is correct. Additionally, MFP doesn't provide a good breakdown of the macro and micro nutrients. The web and mobile interfaces are well engineered. The social integration could be cool for someone that is into that kind of thing.
This application has the cleanest user interface implementation in my opinion. It also has a few ways to add food: text, camera, and scanner. I didn't use the camera so I can't speak to its ability. In terms of features, the base feature set for this application was the sslimmestlimest of all. It only has a calories and exercise tracker. It also has some social features which I don't care about.
I am a data geek and love to dig into the details so it isn't hard to fathom which application that I ended up using here. Also the ability to add biometrics for ketones made me land on Cron-o-meter as my winner. I have been using it now for a straight month and have nothing bad to note.