I don't think anyone can tell which one is better for you.  What I can do is give you a description of both balls.

SPECIAL AGENT:
Special Agent has a strong cover that can handle heavy oil with ease.  It has a smooth reaction thru out the entire lane.  It's not a great ball for playing deep angles.  It is a great ball for playing straighter on the lanes.  From what I have seen this ball would work very well on heavier tough patterns.

NO MERCY:
The No Mercy, just like the special agent, has a strong cover that can handle heavier oil with ease.  The No Mercy's reaction is a lot different than the special agent.  It has a very strong mid-lane like the SA but the back end is a lot stronger.  The No Mercy's back end is not flippy.  It has a very strong powerful arc type reaction.  I have found the No Mercy to be very controllable on tougher patterns.  The NO MERCY is also a ball that can be used to play the entire lane.  This is a great ball for playing inside angles.

So pick your poison.  SA has the strong mid-lane and very smooth back end.  The NM has a very strong mid-lane and equally strong but controllable back end.


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HAMMER NO MERCY is Un-freaking real!  Using this ball is like cheating!