Ask HN: Which JavaScript frameworks do you use?

For my Bachelor Thesis i am doing all little research about the usage of webframeworks. The Thesis is about isomorph JavaScript based frameworks but i am also interested what else do you use. Please evaluate your framework under the following aspects: 1. Time needed for Learning the Framework (in Hours) 2. Overall Development Speed (0-3 Points, greater better) 3. Maintainability of the Code (0-3 Points, greater better) 4. Why did you choose that Framework? I know its difficult to define or measure those things but it will get a helpful overview for my thesis. Thanks in advance for your Time! :)