It's easy to use and understand at least if you have some experience in programming and OOP principles. The documentation could be much more thorough. I think this will definitely improve when there are 2 or 3 new version releases per year (as it happens since CI was released). However CI does not support SQLite, so if that matters, you should look out into other frameworks. We used it for an online store platform where users can manage their own products/products list within our system. It's easy to use. The documentation is helpful and there are many examples available online. This is a great framework if you want to build an ecommerce site. There are too many modules available which can be overwhelming at times. I have used this to build several ecommerce sites and it has worked out really well. We were able to get our website up and running in a matter of days.