The two booster packs are roughly equal in value, with the Solgaleo pack offering a slight advantage in terms of competitive potential
However, Sylveon actually saw a dramatic price spike upward in early April, rising from $480
Pikachu cards across all past sets, promo cards, Championship cards, and special releases have all seen periods of price appreciation the past several years
While we wouldnt have the full block until 2013, Return to Ravnica brought powerful new tools (Abrupt Decay, Sphinxs Revelation, Cyclonic Rift, Rest in Peace, Dreadbore) and one unassuming but eventually problematic megaguildmage/one-mana planeswalker in Deathrite Shaman
You choosing, even from a restricted selection of cards has a lot more disruptive capabilities and random can do worse still