With the LOD it's no biggy and you can find an amp that has a preferred balance but INKs is right about the overall quality of the iphone amp (if similar to the touch 4). My issue with it is the player portion. I was comparing my touch 3 to touch 4 again yesterday, and I still prefer the 3 via LOD and stock player but as a stand alone, you can tell the amp is better on the 4 when using EQU as the comparison player. I prefer the EQU player on the 4 but not on the 3. Try using EQU as your player and you may feel fine about the going straight in sans amp. If the iphone 4 is similar to the touch 4. It's a bit cool and could use a better harmonic with it's stock player.
I suspect your holding off more comment while breaking them in. Good on you. While I can usually get the jist of an IEM early in the process even if they move subtley there after, I found that these do take more time. They won't warm up, open up and not sound mid-centric until you run them hard at the end.