both the x10 and tf10s are many tiers above the S4. I found the S4 to be extremely muddy and bloated. Silibilance wise, the TF10 will be fine with majority of songs and genre, it will add a nice zing to techno/pop that wont be found on the x10. The only downside is that the vocals may seem a tad recessed (V shaped), but still as detailed (if not more detailed) than the X10s. I think many consider the TF 10s to be one one of the top tier universals (priced at 400 at release) and one of the best bang-for-buck iems out there at its current price. The caveat being that if it doesn't fit, you'll very much dislike them.
Overall, while i'm sure that which ever you choose, it'll be a much better experience than the S4s.
If you can, i'd go demo these two iems at a local audio store, figure out which you like better and if it fits before dropping 150 on these :)
Also, while these don't really fall into the requirements that you are looking for, there has been a lot of good said about the GR 07s and EPH 100s which are both within the same price range. They are more balanced compared to what you've listened to so far and are pretty sturdy as well.