UR Tempo wants this somewhere between P1P4 and P1P7, and the price it pays differs from every other archetype that opens the pack. The Sneak line is not a discount in a vacuum: it is conditional on having an unblocked attacker you can spare, which means the card grades on how reliably your deck produces evasive or unblockable early bodies. UR Sneak, the cleanest home, runs flyers and one-toughness threats that swing for two and bounce themselves cheerfully; the trigger you surrender is replaced by a card-and-a-half of forward motion, and the returned attacker re-deploys next turn off the mana you saved. GU Tempo can run it as a second-copy effect when its evasion comes from trample, but trample plus Sneak is the worse trade: you give up real damage on a bigger body to save two mana, and the bounced creature costs more to recast.
The format physics are kind. Speed is medium, the 2/3 blockers that crowd the common slot mean a 2/1 flyer or a menace body gets through more often than not, and the removal suite is mostly sorcery-speed (Stomped by the Foot, Bot Bashing Time), so the attacker you plan to bounce survives to declare blockers. The line is also resilient to instant-speed answers in a way that flatters it: returning the unblocked attacker is part of casting the spell, so by the time the opponent gets priority, the creature is already in hand and Grounded for Life has nothing to point at. Maindeck in any UR or GU deck that opens it. The hard-cast floor is real but dull, so a third copy is a sideboard question, not a maindeck one.

