I have different opinion here.
I did a small test when I borrow my friend's GigaWork & Inspire T series satelite (with titanium tweeter) back to home. I have MegaWork 510D and MicroWork with me, so what I did is to swap the satelite between GigaWork, MegaWork, MicroWork and Inspire, subwoofer used is MegaWork.
The result, IMHO,
1. Inspire is the worst. No focus at all.
2. MicroWork is very forwarding, may be good for those like rock and pop.
3. MegaWork has the depth, better sound stage than MicroWork, easy on ears too.
4. GigaWork.... very different sound compare with MegaWork, very laid back. I don't enjoy much, and no idea if woofer matching is the problem here.
Overall, I prefer MegaWork over GigaWork.
And regarding Z680, I listened once at shop. My personal opinion is it may be good for gaming or DVD playback, but not music playback. Too much bass and treble for my taste, tonal balance is out.