Don't expect much.
This DLC comes with 6 missions. At first mission we grab our new vehicle and learn to use it, and after this we learn about some secrets and go after some scientists, and it takes 2-3 hours to finish.
Most disappointing thing is we cant use our characters on our missions (except the end, at the end we just walk few meters, that is all), we are just able to use Firewalker, and our team dont speak during missions even at the end.
Firewalker is a fun vehicle to use, It has great potential, but dont expect from this DLC much, after played it it gives me a sense that Bioware just made this DLC to introduce us their new vehicle and they will use it in future for other DLCs and maybe for Mass Effect 3.