I have the EF-6 and love it with the T1, HD800, and even the TH900s. Now, with the HE-6, it's a different story. Since I am definitely in the minority, I am thinking that it doesn't do a good job maybe because:
1. I listen almost exclusively to classical music and the EF-6/HE-6 combo can't handle the wild dynamics swings of Mahler, Bruckner, etc.; and/or...
2. My sources (i.e., I've used an Oppo universal player, a Marantz SACD, and a Rotel CD player (each costing about 1K, mind you) do not have enough power and, as such, do not do the EF-6 justice.
Whatever the reason, the EF-6/HE-6 combo is definitely underpowered and tends to distort with wide dynamic/volume swings. So...buyer beware!