As we talked about before, the issue with Gyruda, Doom of Depths is that, discounging a ramp spell on turn two, it locks you into only playing one spell for the first three turns of the game
And finally, Yawgmoth, Thran Physician is always in need of a reprint, whether in the 99 or at the helm of a deck
All in all, the Beginner Box is a very basic and non-rewarding entry, and I would recommend a lot better options such as the Starter Collection, or buying a preconstructed commander deck by visiting your local game store and finding something that rings with you.
It remains to be seen if Wizards will release more cards of such rarity in the future.
Academy Ruins
A huge chunk of the value of Double Masters comes from the box toppers, so if you're thinking of buying the set, splurge on a box (and cross your fingers that you run well) rather than buying random packs