I don't think they do them anymore but I love my fal pro domino that was a cheapy off ebay.. it's like a thermatex without the filling. prior to that I always used waffle ones then leave a thin stable rug on if really cold but this is a nice inbetween (it was a fab post hunting rug too!)
I've just bought a protech masta and I pop a thermatex on top if it's cold. I'm really impressed with the protech as it regulates the heat so they don't get too hot or cold. my Thermatex is really old but is still looking good.
I have a Premier Equine buster waffle cooler for milder days (it's a different material to other waffle rugs and quite thin, but mine gets quite hot when he travels), and then I might pop a stable rug on top if it's especially cold. I've just ordered a LeMieux thermocool rug (similar to a thermatex) in a sale as a warmer travel rug and for drying off after hunting, but I haven't seen it in real life yet so will have to see what it's like!