As far as I know, there is only one way to root the Maxx if you are on 4.4.4. I have not done this myself, but I know that I have read others report that it works.
The instructions are here:
http://forum.xda-developers.com/showpost.php?p=60085162&postcount=189
Note that if you are on the current build (SU6-7.3) you will have to downgrade to the older 4.4.4 build SU6-7 and then refuse any OTAs before you start the root process. This will probably wipe the phone, so back up photos and video and whatever you need to from storage.
Note that the Maxx will not allow you usually to use RSD or fastboot to load an older firmware version, but it will if the bootloader version is not being downgraded. All of the SU6-7 builds use the same bootloader version, so you'll be ok. Unfortunately, you cannot go back further and use the Sunshine app to unlock the bootloader.
The process looks pretty complex to me, but, as I said, I know I have read plenty of people who have completed this.
Make sure that the phone is fully charged when you start.
I think all of this is in the instructions that I linked above, but I just wanted to reiterate the important stuff... and -seriously - read those instructions C A R E F U L L Y .
