You can either buy a DIY kit and assemble it yourself or buy a preassembled one. The DIY ones are cheaper but there are a ton of write ups on how to assemble it and upload the firmware to it.
There is also the benefit of SD Card data logging as well as Bluetooth functionality. I have my Android head unit running Shadow Dash so it displays all my gauges. The logging is setup so every key cycle it starts a new log. Anytime I have an issue I can go back and download the log to review data.
Comparing the difference in cost you're a couple hundred over with the DBW controller but you get a full standalone ECU with years of support behind it.
I never heard of the FT550 before so I can't give any pros or cons to using that. I just know what's worked for me and I have had experience with AEM, Haltech, Hondata, MS, and Cobb.