One has a stronger cover and weaker core:
Polar Ice -- Urethane (solid version and pearl version) with a Pancake core
The other has a weaker cover and stronger core:
Taboo Spare -- Polyester with a Dynamic core
When all is said and done, which would you rather have for dry lanes and/or spare shooting.
Option #1: Some may say the Polar Ice would have slightly better traction and control due to the Urethane Cover and Pancake Core and would be a better Dry Lane ball therefore making the Taboo Spare their 10-Pin spare shooting ball.
Option #2: Other may say the Taboo Spare would have better skid, roll and carry due to the Polyester Cover and Dynamic Core and would be a better Dry Lane ball therefor making the Polar Ice their 10-Pin spare shooting ball because the Polar Ice will hold the line to the 10 pin better thereby eliminating that possible last second whif of the 10 pin due to the Dynamic Core deciding to suddenly slightly "jerk" off line.
What would you do?
And to some, it might appear that you just need one of these and let it serve duel purpose for Dry and Spares... but I am leaning toward Option #2 personally.