I've been perusing the forum and noticed this topic wasn't out there, so I need to ask the question.  Do these two compare any?  I have a Defiant Soul, and can get away with playing up 5.  This is what my physical abilities are allowing right now (I'm a converted lefty, three years running and not even attempting to turn the ball).  I was wondering if it would be worth it to purchase the Sinister.  Will provide a photo of the layout first chance I get (it's sitting the shop right now).

IMO these two balls are very simular. I do have both. I personaly would look at a different ball so you wont have a simular reaction. The Sinister may be a touch stronger, depending on your lay out.

I have found that these 2 balls form a good 1-2 punch.  I had the Sinister drilled pin under ring with CG kicked out and the Defiant Soul drilled pin over ring and CG kicked out.  I found that I could start with the Sinister playing up 5 or 6 board, then change to the Defiant Soul when the broke down.  Both of those balls were OOB surfaces.

The chatter at the pro shop comparing the Sinister to the Defiant Soul, similar reaction shape but a one arrow difference in strength.