Pros of REB:
Counters all counterspells and all blue draw
Destroys and/or counters Tezzeret
Can kill lots of Fish creaturesStops Tinker
Pros of Dispel:
Counters all counterspells and all instant draw.
Counters all Vintage instants like Darkblast, Vampiric Tutor,
Swords to Plowshares,
Ancient Grudge/Rack and Ruin, Ad Nauseum, Dark Rituals
Can be pitches to Force of Will and Misdirection in clutch situationsCan be fetched with Merchant's Scroll
You will most likely always be able to cast this card
Cons of REB:
Not a blue spell
Needs a red splash
Opens you up to the risk of color screw (ever sit with dead REBs as your opponent Ancestral Recalls?)
Cons of Dispel:
Cannot destroy and counter Tezzeret, Ponder, Merchant's Scroll, and Tinker
Cannot kill any Fish creatures
I am going for 4 foil Dispel please

Note:
Both REB and Dispel loses to Yawgwin
