Used the gold but not the copper.

They are on a similar level of overall performance.  The choice between them becomes more a matter of personal preference.  My preference prefers the Triple.Fi 10.  While people complain about fitment, glue problems, and wire problems, I feel the Triple.Fi 10 offers a bit more to the table.  I enjoy listening to music more with the Triple.Fi 10.  I think it has more wow factor when recreating the music.  Monster have made some nice earphones.  The MTPG for example doesn't really do anything wrong.  The frequency response is smooth and extended.  The notes are clean, well textured, and controlled.  I can argue about little details but much of that will be issues relative to my personal preference.  At the end of the day, I would prefer to be listening to the Triple.Fi 10.  Actually I would probably be listening to one of a few other options out there, but that is again preference. 

Just an FYI for the OP, Golds sound nothing like Coppers.

those 2 are .... all about preference, but i can tell u the fit for TF10 is hideous unless u wanna mod them, MTPCs are fine but insertion depth seems to be a sensitive topic...

but i still suggest the MTPC

MTPC FTW

I prefer the TF10 to the copper 

TF10

I have both and go back and forth as to which is my favorite. The TF10s fit me very comfortably with Sony Hybrid tips. The Coppers are definitely sensitive to insertion depth and tip type. I ended up with Sony Hybrids and fairly shallow insertion. I wish that I could pick one so that I can sell the other.