The reason I choose TMV is simply because it is leveraged, a closer comparable to that miners are leveraged position of gold price. I understand there are reasons people don't like using the leverage ETFs, but this is only for short term.
Since the beginning of this year, TLT and GDX have shown increasingly positive correlation. When we look at the inverse TMV/TBT alone. They are showing some divergence in both and momentum indicators. While I personally think we will enter a normal rate world in the long run (which potentially means bear market for gold if correlation of GDX and TLT did not break), in short term, we should see the re-bounce of GDX .