I'm putting down my money for a pair of T1s next week. I'm only about 50mins from ACS so I'm going to their Banbury HQ and they will be taking the impressions themselves.
I think the thing that comes through to me from the various posts and the e-mail exchanges I've had with them leading up to my decision, is that your money is getting you more than just a top-flight IEM, it's also buying you into a customer relationship that goes way beyond anything you'd get from any mainstream manufacturer like Shure or Sennheiser.
OK, so ACS give a warranty, but it seems quite obvious that they go well beyond the normal level of customer service. To a degree this is to be expected with a bespoke, custom item, but even things like the very reasonable charges for repair/servicing outside of warranty are to be applauded. No doubt this is because until recent growth in interest from audiophiles, ACS' stock-in trade was with music professionals, from artists to producers and recording engineers.
To me, purchasing a quality product from a company to whom I am more than just a number, has real value.
The bonus is that assuming the T1s work out as well as I expect them to, I will be able to fund a big chunk of the cost by selling my other IEMs, and full-size phones, which I just don't use enough.
Really very excited about getting them.