I've recently switched from Transparent Ultra to MIT Oracle V3 speaker cables. The Oracle V3 provides a blacker, quieter background, is smoother, more linear, and much more extended at the extremes. Resolution and imaging are also superior. How the Oracle V4 compares to TA Reference may be a closer call. In my system the TA Ultra had very good mid bass, but seemed dry, and lacked sparkle in the high end.
If you do go with the Oracle V4 you may need to have MIT update your cables with longer leads from the network box to reach your speaker's terminals. You also have the option for bi-wiring.
Good luck with your decision.