If I steal control of a repeat spell with Mystic Reversal, do I get both instances of the repeat effect if my opponent paid for both?

Ruling: Yes, you get all instances of the repeat effect that were paid for. When you gain control of a repeat spell, the repeated spell effects are part of the original spell which has been finalized and paid for, so gaining control doesn't change the fact that the repeat cost has been paid.

Sequence:

• The original spell is cast and repeat costs are paid
• The spell (with repeat effects) is finalized
• Control of the spell is stolen
• The spell performs its effects the number of times corresponding to how many repeat costs were paid

Nuances:

• Repeat effects don't go on the chain separately; they're essentially appended to the text of the original spell
• You get 1 spell that performs its effects multiple times (twice if one repeat cost was paid, three times if two repeat costs were paid, etc.)