tracking ability definition

I would make my choice depending on which sound quality you are seeking. From their description - I have not heard either cartridge - I would say to go for the Trackmaster if your taste runs to classical, vocal, acoustic jazz, or if your system is too brash or too lean. The Pro 40 may be the ticket for rock, dance, hip-hop or if your system sounds a bit tame or warm. Of course, these would be generalizations.

I forgot to ask, but I assume that you are using a Technics 1200 as your deck.

I have heard the Ortofon Super OM-40, which is similar to the Pro 40, I think that you will just love it. The 1200 is a great table as well. Best of luck.

Do not confuse tracking error, which is the degree to which the stylus remains tangent to the groove as it traverses the record, with tracking ability, which is the ability of the stylus to maintain constant contact with both groove walls while playing highly modulated passages. The importance of this is two fold, if the cartridge loses contact with the groove wall, the sound will distort, but of more importance, when the stylus engages the groove wall once again, it can damage the soft vinyl and essentially take a divot out of the groove wall, much as a golfer takes a divot when swinging low upon tee off. This damage cannot be reversed. Interestingly, proper tracking ability in modern cartridges has more to do with the compatibility of the arm and cartridge, and correct alignment geometry, than in any specific tracking problems of the cartridge itself, Decca cartridges excepted.

Raul, my friend, I would agree with you as far as test records are concerned, but most of the modern cartridges that I have used in a sympathetic arm will track all modern, undamaged, records without tracking distortion, the Telarc 1812 excepted. I would certainly defer to your experience though, as you have tried far more cartridges and arms than I ever will. Or anyone else probably will as well!

Fadeawayman, click on Rauls system if you want to know why he is a true authority on all things analog and has a fantastic base of experience as well. It will be worth it.
Marty