Well, I can tell you this. The Sheriff Department in Michigan (where I am employed) tasked me with research "environmentally friendly" cleaning possibilities. I do NOT work for the company and I believe it is extremely expensive to utilize. While working on this, I made DIRECT contact with two end users. One of them being the Michigan State Police Tac Team Commander and the Other being the Border Patrol Head Firearms Trainer.
MSP states: Went to tac team competition with MP5's. Took ONLY 2 guns and one of the two was cleaned standard Hoppes and then oiled in accordance with HK and the other cleaned/lubed (one stop shop type product). Allegedly the shooting time was split between all members and the Gunzilla gun ran the smoothest without failure and the Hoppes gun had hickups toward the end.
Border Patrol advised me, he started using it on his muzzle loader personally. From there began experimenting with it on the BP M4's. Failure rates on the range was allegedly greatly improved. When I asked what type of controlled testing was conducted, he laughed and said if he don't stop to make em' run, then it works better! He further explained the wear time on the firearms has NOT seemed to change, but the malfunctions between part replacement had reduced drastically. To that he added, "You really gotta keep using it for yourself to believe it."
Two of our Range Instructors went to Tennessee for a LE Carbine Instructor class. One used Breakfree the other used Gunzilla. I prepared the guns for them. They were both newer Bushmasters 16" carbines with the same number of rounds through them +/- 10%. Prior to them leaving with guns, they were cleaned with break cleaner and then the appropriate lubricant applied to each gun (UNDERSTAND, I WAS NOT "one stop shop guy). My goal was to prove them wrong.
Per the Instructors, they shot about 800-1,000 each and NEITHER gun had ANY malfunctions, but both agreed the gun cleaned each day with Gunzilla was significantly easier to remove the carbon from.
This is not an endorsement and I STILL believe the product is over priced, I also believe it works well. Does it work well enough to switch from other working methods, that is up to each of us to decide on our own. If you want a product that is environmentally sound, it is one of the only true options. I personally have NOT switched yet...old habits die hard.