Rhino (though that's nothing to do with my username, honestly). I have rhino rugs going strong after 10 + years, I have bought 2 weatherbeetas in that time and the best one lasted..... nearly 2 weeks!
Although I do prefer to try and buy 2nd hand rambo's as they are the best of all IMO
Rhino hands down , they fit lovely and also come up lovely in the wash ( as long as you wash according to label of course ) I've sold second hand , old as the hills ones ,on eBay and still made good money.
I too love Rhino's BUT... it does depend on the shape of your horse!
My TB fits hie Rhino perfectly and weatherbeeta's rub his shoulders. However for my bigger horse Weatherbeeta's every time. They fit perfectly and never rub or leak. I also like the fact that Weatherbeetas neck parts seem more padded for when its cold.
My rhino neck cover is think like a l/w with no padding at all.
I have just bought my big horse a Saxon (weatherbeeta) 1200 heavy combo and its fab- and a bargain at £59.99!
I would say Rhino's are tougher, harder wearing and thus longer lasting. But whetherbeetas are good too. I'd double check the fit of both before buying though as said already, they come up slightly different.