Tempo Mage was the strongest Mage deck for months but was finally dethroned after the release of Mean Streets of Gadgetzan.
Reno Mage lists are much stronger in the current META and although this deck may not be seen as one of the Tier-One lists it’s strong enough to take to legend for sure.
The only real drawback is the lack of card draw, but if you manage your resources well you can climb the ladder with a good win %.