I used to own the BA200 and SE425.
The BA200 sounds clearer and more airy, but the bass always leaves me wanting for a lot more. The instrumental separation is really good and you can clearly hear each instrument in its position side by side, instead of them being just layered over each other.
The SE425 sounds a lot heavier compared to the BA200. However, it's redeeming point is its mids. It's really good for rock and roll songs that does not much speed, thanks to its high emphasis in the mids. You will be surprised when you listen to it for the first time and wonder whether's it's really a BA iem because of this. The sound signature eventually grew on me and i always went to the SE425, making the BA200 my backup iem. Bass is still slightly lacking, but it's sufficient to make it bearable.
I've used both IEMs with the small shure olives (i have small ear canals), so your mileage may vary if you prefer silicon tips. Build quality-wise, the cables of the SE425 really can take a beating. Take note that my source was a 3rd gen iPod Touch, so the sound signature will definitely sound off to me as the output impedance was slightly too high for these sensitive IEMS. This is definitely noticeable after I changed to the latest iTouch and things sounded smoother with BA iems.
I no longer use these iems as they are broken. The BA200 failed at the connection point on the left earpiece while I accidentally snapped the nozzle of the SE425 by crushing it with a chair.
Have you considered getting customs? I've since moved on to the JH-5 and the leap in quality is huge.
