CodeIgniter was great back in its time but has been supplanted by Laravel in its organization of code. However what CI did well, in my opinion, is it lets you spin up a MVP in a really quick turnaround time and effective enough for small businesses.
Codeigniter is still great. I was always Symfony guy but last year I've ended up in a company that had software build on CI and I really like it. Of course it's totally different than Symfony but it's simple, allows for a lot of customisation (we introduced Laravel Blade templating system). Of course you should always thing about your project requirements and future development. Think also about how easy it is to learn in case you will want to extend your team.
