From the Bayou Man:
"I hear the Studio V as having ever so slightly emphasized treble, which lifts the sound in a nice way. Certain details are more emphasized over the iP4 and HM-901, but SLIGHTLY is the key word here...all these details are still very present in the other players. The Studio is a tiny bit more holographic than the iP4 due to its slightly more spacious and separated sound. The bass line in the Studio was also surprisingly solid, keeping up with the iP4. I didn't expect that. I couldn't find anything that the iP4 necessarily did better than the Studio, as the differences held up in my other test tracks."
Other than my "on-hand" 6-12" fishing rod, I can't claim to play a music instrument(much less 5!!) , however:
While I agree that the Studio V 3rd Anniv(slightly warmer than the Studio V) has a very slight emphasized treble over the iphone4s, my interpretation of the iphone 4s compared to the 3rd Anniv is that its more V-shaped while the 3rd Anniv is more analytical and flatter in response. The holigraphic, spacious and separated sound of the 3rd Anniv is also seems more dynamic in range and placement. I found the bass to be slightly exaggerated on the iphone which reminds me a V shape too.
Listening to Alison Krause, her voice seems much warmer/slightly compressed on the iphone while the 3rd Anniv, sounds clearer and dryer/analytical on the 3rd Anniv. I have my Tralucent T1 to warm up the analytical, dry 3rd Anniv(they are velcroed together). I still get the flat, analytical sound of the 3rd Anniv, but its warmed up.
I would say for a critical listener, there is a bigggg difference between the iphone 4s and the 3rd Anniv. After having the Studio V, I did find the Studio V 3rd Anniv more warm, but still needs my T1 for the warmth I like. I'm hoping the X5 will take the place of my combo.