I believe that there are several different programs people have made to determine a deck's power level, but it is helpful to think about what cards are in the deck, what
the general strategy is, and how seriously you intend to win with the deck. Vadrok is such a cool commander, I've always wanted to try building him but haven't had the chance yet. The thing about EDH is, if your deck has a bit more power than the other players at the table, they can
band together and take you down. I've had a
Najeela, the Blade Blossom lose to other, slightly more casual decks because the table saw me as the threat and got rid of me first. (Joke's on them, my lgs gives a pack to the first one out on commander nights.
When looking at and editing the cards in your deck, you can select whatever version of them you want. If I want the Premium Deck Series: Graveborn copy of
Verdant Force in my deck, I can specify that. This can also get you Secret Lair card styles, and can change the cards from foil to non-foil.
Good luck!