I dont have one but i do have a Bucas Smartex which is similar in that its a cooler/turnout. Ive found it invaluable as my horse wouldnt be stabled to cool off and hated clippers. The only issue i have with it is that it is awful for slipping unlike my Mark Todd rugs which stay in place perfectly so i imagine a combintion of the two would be amazing! ;-)
I have one with the neck cover and I also have a Thermatex - the Thermatex is by far a better rug on all counts.
The Mark Todd doesn't wick anywhere near as well as the Thermatex and the fit isn't great. I find the neck to be too big for my chunky cob ( not the neck cover but the fit of the rug around the neck ) so the rug slips back and then it digs in around her shoulders - if that makes sense?!
The neck cover is quite big, it's too long for my cob so I have to push it down or it would be over her ears It's also quite a wide fit so if you have a thinner necked horse it might be far too loose.
I'd never buy another one, I'd save up for a Thermatex instead.