Yes it's a strong deck, yes it's going to stay strong, NO it is not worth spending 3000 dust on though. Few decks are ever so definingly strong that you should spent 3k dust getting them (that's 2 legendaries...! in real money value, that's neighbourhood of $40US, I think?)

The "best" hearthstone decks only win 52-55% of the time. Your current decklists might already have a winrate close to 50%.

Decide how much that 2-5% is worth to you... spending dust on netdecks sometimes isn't a very good return on investment.

just my opinion! I see a lot of people disappointed when they craft a strong heathstone deck, and don't have any more fun or success with it than the decks they were already playing.