I mean, a couple months ago I bought an R9-290 with the idea in mind that I'd get another for crossfire. I've managed excellent temperatures with the stock aftermarket company coolers provided. Haven't had to set up a loop for them, and probably never will. Both my ASUS cards keep under full load at around 69-75C. If I disable crossfire, the main card doesn't even break 70.
Before this I had dual R9-280's and I only had these with the idea that I'd upgrade to an R9-295x2 when it became financially acceptable. It didn't. I know AMD made small tweaks to the boards on the dual gpu on single pcb build, so you do see very mild gains, and possibly less tearing. I wouldn't say it's worth $80 though.