Like most Magic: The Gathering cards, the value of Phyrexian Metamorph depends on a few consistent factors: its rarity, the printing and finish (regular or foil), its physical condition, and the set it was printed in (Double Masters)
Can you honestly say you knew these cards
Being completely colorless makes the deck's mana rocks highly effective and there are 17 total peices of ramp in the stock list
XX for an X/X creature is on the weak side, so that meant there was some room to add something cool
The consistency of quality back then was laughable
Thunder Lasso has a strong effect and can win some games, yet I think the stats it adds to the board are small and thus it is unlikely for me to see this perform significantly better than a 3 mana 3/3 creature - and that is in addition to the fact that sometimes you wont be controlling a creature and the Lasso ends up being an effective mulligan in those games