Hi guys,
Just thought I'd post an update as I've now got both the FXT90's and the MG7's. As an upgrade from the S4's the MG7's are a major step up in the low-end response but quite similar, maybe even slight recessed, in the mids and treble although I feel that after some burn-in this will allow the MG7's to open up. The separation and soundstage is about the same. The FXT90's are clearly inferior in the bass department but mids, treble and soundstage is slightly better, although the treble can be harsh at times, again with burn-in I'm guessing this will be tamed. Separation is again similar maybe even better on the S4's.
Now as an alternative to the TF10's the FXT90's are inferior in every aspect, whereas the MG7's are better with bass, in fact the best I've ever heard, but lose out on just by a bit on everything else. The mids and treble are just crystal clear with the TF10, the FXT90's are good with these as well but can get harsh at times. The soundstage and separation is the best I've ever heard on the TF10's and I guess that's expected with a triple driver earphone. Yet as noted before the fit of the TF10's make them lose out in my opinion.
So after months of searching I've decided to keep both the Atrio's and JVC's, the Atrio's being my primary pair and occasionally using my FXT90's when I require more treble. Certainly as an upgrade from the S4's the Atrio's are a better choice. To be honest I think I expected more from the FXT90's, especially after reading about them on the appeciation thread, having said that they are great earphones and I highly recommend them to everyone. In a perfect world I would take the fit of the Atrio's or JVC (as they are both pretty comfortable), the bass of the Atrio's and pretty much everything else of the TF10's!. The TF10's sound will certainly be missed but I know the Atrio's are not too much of a compromise, I will be happy with them for years to come.
Thanks again everyone for your help/advice.