Has anyone tried the ACS T15 monitors?

[john_the_bass]

I know this is partially covered in the earplugs thread and I've sort of looked at it on the thread I started that Dood replied to, but has anybody used the ACS T15 monitors? These are the monitors that are designed to plug straight into the ER9/15/25 custom moulds, in place of the filter (no adaptor required as is the case with the Etymotic drivers).

I'm just wondering how they compare to another set of earphones (which is presumably what you hear the music through from your wireless receiver and could be substituted with earphones from any brand).
I'd like to be able to use these not only as a monitoring system, but for portable audio as well and wondered what the quality was like? They're about £99 from blueplug.co.uk, which is about the price of a mid-high set of earphones.