I have four pieces so far, upgraded to 830 (will consider upgrading to 840 after tier 5 research started tonight, unless I get a FIRST legendary soon...).
I love the concept, but WQ has gotten me to 838 (no drops from the 3 heroic and 4 normal dungeons I've done; I'm not much one for group PvE, hence loving the open world set bonuses). I'm probably going to out level even fully upgraded sets by two weeks from now.
Is there going to be more to them in future patches? I'm probably going to drop them in my bank soon...