Just out if curiosity, how do you figure this?
Disclaimer: this is my personal experience from at least 5-7 years ago, so may not be totally current although I have handled friends' RAT-1 and 2s fairly recently.
Owned several RAT 1 and 2 folders over the years (early on in my knife collecting especially), invariably found the blade design and choil to my liking, but the combination of HT running a little soft (would not hold an edge as well as other AUS-8/8cr13mov knives I owned), the scales being a slick when wet, thumbstuds being a bit slippery, and the slightly odd weight distribution combined with an admittedly strong liner-lock that was uncomfortable to close for me - found Spyderco linerlocks and Benchmade AXIS locks easier and at least equally reliable - made me decide against the RAT-1 for EDC. Pocket clip also caused hotspots and blisters when I would have to really grip it hard for heavier work.
I think with slightly better materials, a tweaked weight distribution, better thumbstuds, and a few other improvements the RAT folders could easily be winners. And they are, the new Zancudo, etc folders are a nice improvement, thereby posing the question when considering what advice to give to OP, why look at the older, related designs if the Zancudo, the newer and improved design, had "problems" as yet unspecified? If the problem is with the design philosophy or the manufacturing (likely same factory/OEM) then it seems logical to look elsewhere.
In the end when considering the RAT-1 for EDC the slick scales and poor edge retention and weight distribution just didn't cut it for me, I found many other knives to be superior for my use at comparable pricing. I believe the Boker Chad Los Banos designs were recently released at the time and I found them much more to my liking for (at the time) $10 more for Trance, Hyper, etc. Of course, I enjoyed my Spyderco Military even more for EDC, but it was a tad big for NPE's, not to mention 5 times more expensive so I just did not use it for "dirty work".
Hope that answered your question and hopefully didn't come off as excessively wordy and/or illogical.