I have been listening to my new Custom 3s for over a week now and believe I have finally found my dream IEMs. Been listening to recorded CDs (all lossless format) like Buddha Bar 9 which really represents the entire sound spectrum and at different tempos too.
Thanks to Ka-boom and Smallcaps for their insightful reviews, which helped me choose the Custom 3s and fork out the dosh for them over the internet.

My reasons why the Custom 3s are the best I have used:
1. Fit great straight out of the box, didn't have to try any other plugs but only rotated the elliptical silicons 10 degrees posteriorly for a perfect isolating fit. Was going to fork out for shure black olives (which I have found were either too small in the small and slightly too big in the medium which prevented me from being able to use them for more than an hour due to pain) if the Custom silicons didnt fit. Just lucky I guess. I can wear these for at least a couple of hours and no discomfort. I think the elliptical silicons really suit my ear canal.
2. Quick and easy to place into the ear, less bulky than the SE530s
3. The material cabling is fine I think. I use the slide-knot and do not get any more audiophonics than other IEMs - I actually think there is significantly less rubbing noise. The slide knot also allows me to get a more snug fit too. The length of cord is perfect. One bad thing though, is the cord will probably pick up dirt and skin oil over time and they can't be wiped down like normal plastic cord.
4. Clarity, clarity, clarity was my first impression. The mids are lovely and balanced. I can separate multiple instruments all around my head. House music and Lo-fi stuff sounds awesome. Still making up my mind the highs, think they might be a little harsh for my tastes on some tracks (likely iTune's fault or still need to burn them in more).
5. The bass is deep, warm, and layered. As I have only listened for a couple of dozen hours, the bass should improve even more over time. The base is better than the SE530 and on some tracks you can feel it in your chest!
6. Sound stage is great, once you get a snug fit. Probably slightly less than the SE530s, but not by much and bloody good for an IEM.
BTW, I bought the FiiO 5 for for a real bargain - $15AUD from eBay (delivered), and want to say that though its nothing more than ok, its is great for the price. I strongly don't think its worth any more than the price I paid though. I find it a little annoying though as the ipod shuffle-like clip faces the wrong way and the cords are thus tucked under your clothes and not straight and free.
Initially I wasn't sure but took a leap of faith based on reviews and gut instinct in buying the Custom 3s. They are cheaper than the Shure SE530 (which are reputed by the majority to be the best IEMs at present) and I prefer the Custom 3's sound signature (a personal preference I guess). In many ways, I am glad I had my SE530s stolen. I am extremely happy with the outcome and hope this post helps others like me.