Phono Protractor. Recommendations?


After purchasing a new Cartridge recently, I'd like to purchase a good protractor.  There are so many available, each claiming to be the one to have, I'm confused.  
What do you recommend?
louisl
I hav a Smartractor and Geodisc. The Geodisc is approximate and good for most applications. The Smartractor is outstanding and very precise.
@wlutke 
How do I find what the correct "pivot to spindle" distance is supposed to be?  (My TT is a VPI Classic 3, my tonearm is the JMW 10.5).
If you want the best, and have multiple arms, get the SMARTractor. 
If you want the best, and have one arm, get the Mint. 
If you want to throw away $20, get the Turntable Basics protractor. 
louisl,
Your spec is most likely 258 mm. Remove the arm and measure pivot spike to spindle center for the actual.