The vocal tips are very similar to the spinfit 100s. But if I had to compare using my untrained ears, it appears that the vocal tips have slightly less treble, bass, and what I call "snare snap/sharpness" (sibilance, perhaps?). But I should emphasize that the differences are so incredibly slight in these areas, I might not even be able to tell the difference in a blind test. The soundstage isn't as wide with the vocal tips as it is with the spinfits, which is the biggest draw of the FD5. If I had to put a number on it, the vocal tips probably have about 80% of the soundstage as the spinfits. All that said, the vocal tips do bring the vocals a bit more forward, but at the costs mentioned above. I might be asking for the impossible from tip rolling, at least in this price range and sound signature, but I'd like to have all that extra treble, bass and soundstage AND the forward vocals.
I will also say that the vocal tips stay in my ears better, probably due to the texture of the silicon. The spinfits are so smooth such that if there's any oil in my ears they tend to slip a bit and I have to shove them back in to maintain the seal. The vocal tips have some roughness to them that seems to help keep them in place.