I got the Jackies but I'm wondering if they're worth that much. They look less refined than CS boots.
The price difference largely reflects the difference in labor costs between Portugal and Britain. That is the main reason that Spanish and Portuguese footwear is often such an exceptional value. Beyond that, both are great boots, very well made from quality materials, and you should have what you like best.
A preference for the appearance of one versus the other is entirely subjective, as both are beautifully finished, very handsome chukkas. I have the Jackie III's and prefer them, not because I have them, but because I'm in love with the mahogany grain hide which just keeps looking better, and I prefer the somewhat less radically elongated last of of the Cheaney boot. I also find Cheaney footwear in general, and the 125 last in particular, exceptionally comfortable. I can't comment on the CS boot, as I haven't tried it.
I have no reason to think the CS boot won't be very durable, but I know Cheaney footwear tends to wear well.
Either boot is well worth the price asked for it.