I did a little digging around and from what i've read, many people think that they are genetically engineered, which was my concern when i first saw them, but i may be that they are a different variety that are naturally lower in fat than the smaller californian variety.
Apparently the name 'SlimCado' was a marketing gimmick for the health conscious, that seems to be making many people wary of it. It just sounds like something contrived in a lab!
But from what I've read, the Florida and mexican varieties are naturally bigger and higher in water/ lower in fat than the Hass and other californian varieties.
scroll down to the second article here:
here's a humorous take:
All in all, it's ironic cuz many people including myself are including avocados for their monounsaturated fats, and here comes the slimcado saying it has significantly LESS of this good stuff....