The best thing I like in MAMP is that the software includes all necessary tools inside the one APP. There is no need to install each software separately like MySql, PHP, Apache MAMP provide all in one platform which makes the life of the developer easier. I also like the user interface which is very simple and intuitive. You can easily create as many virtual hosts as you wish within a few clicks.

I like that you can setup an apache/mysql/php stack very easily. I also like that you can provision sites from the UI without having to go in the apache settings, and use different versions of php in each site.

The simple interface makes getting a server up and running so simple. A click of a button gets your Apache and MySQL servers running, and then you've got a folder where all your 'sites' can live. Everything is customizable, so if you're more familiar with server stuff, then you can set it up however you like. But if you're not, MAMP make it really easy to get your site up and running locally.