Cisco Firepower is the conglomeration of ASA and Sourcefire. With Firepower Thread Defense the two codes are merged and you get the benefits of both worlds. FTD devices are not longer managed by the one off of ASDM and JAVA! There are multiple ways you can manage a FTD device.
FDM - Firepower Device Manager, a web interface for managing independent Firepower devices.
FMC - Firepower Management Center, a central controller to manage, investigate and troubleshoot all of your FTD devices. Available as a virtual device or an appliance.
CDO - Cisco Defense Orchestrator, a cloud based SaaS offering that serves as your central repository for many things Cisco security related.
Each of the different management platforms has a different subset of supported features. For the most part the critical core features of FW,IPS/IDS,VPN and troubleshooting are available in each. Not all features have made it natively into the GUI's of FTD but more features are ported with each release. For features that are not fully migrated there is a tool called FlexConfig which takes the ASA code and inserts it into the FTD device. It is a little cumbersome but can get the job done.
In my lab infrastructure I leverage both physical devices and virtual. I leverage a FMCv as my management platform and all of my lab examples demonstrate the configuration through it. In the future I will look to integrate CDO capabilities in my lab. Below you will find the documentation of each of the different feature sets I integrate.