Is the MoFI UltraDeck wit the MasterTracker cart the best TT solution @ $2,499?

Best at $2500? That depends on your needs. I demoed the P6, 1200GR, and UD. I could have lived with any of them, but the UltraDeck is what lives in my system now. 

If I was a cartridge swapper, the GR would have been a no-brainer. 
If I was willing to commit to the simplicity of Rega and stick with Rega carts as a "set it and forget it table" then I would have ended up with that one. 
I liked the flexibility of the UD for various carts down the road, and I preferred the sound of the UD vs GR in a demo. 

I emailed MoFi regarding the tonearm. Here was the response:

The UltraDeck Tonearm Effective Mass is  25.14g. We have mounted many cartridges from Ortofon, Grado, Hana, Audio Technica, Denon, and others that work great with both of our turntables. You want to avoid any cartridges that are specified as high compliance but the majority of today’s cartridges are either medium or low compliance and will work great with your turntable.

 

The compliance of our cartridges at 100Hz is available;

Studio Tracker

 Static compliance : 35 x 10e-6/dyne

 Dynamic compliance : 8 x 10e-6/dyne

Ultra Tracker

  Static compliance : 35 x 10e-6/dyne

  Dynamic compliance : 10 x 10e-6/dyne

Master Tracker

  Static compliance : 40 x 10e-6/dyne

  Dynamic compliance : 10 x 10e-6/dyne