the red dragon has a extra fan, also requires a extra 8 pin power adapter
is meant to be used for "heavy2 overclocking, but these rx are not great overclockers
the advantage it has over the cheaper is that it can work more quiet under heavier loads, since the 3 fans can spin slower to keep it cool
i personally don't like powercolor brand, but all i have seen is good reviews about the red dragon one
if it fints in your psu, case and budget, seems to be a good buy, if not, the 2 fans shouldn't be really worse
i personally buy sapphire only, but powercolor seems to be doing decent cards now, so is a valid option