i think the cube does metal better and the viper does classic rock better
personally i would save up for a Peavey classic 30/Valveking TBH
Vintage V-100, EMG 81&60
Chapman ML-1

Jet City JCA20H
They're both good... but the Vypyr does both Rock/Metal better IMO.

And I'd rather a Vypyr than a Valveking... VKs are terrible.