In the broad sense, those are all cousins to each other. Same basic design if not compatible parts. O'doyle has it right - get the one with the best backing. I have had 2 (paid 25% off for one, and a warranty replacement) - and I broke them both. Totally my fault for starting the compressor when it had pressure on the output line. I used a giant inline filter and it took a long time to get that to pressure before air started into the gun. I would pressure the filter, then turn off to cool, then start to fill the gun. I sheared the motor shaft on both of them. I am still looking for a replacement to fix the one out of warranty.
I would recommend the Xisixco GX CS2 or GX CS3 pumps instead. It is slower, but has been very reliable.
Took a chance - bought a GX CS3 - Airgun Nation Just bought this CX2 portable compressor - Airgun Nation