I just got back from the NAMM show where Dale delivered my AS1b set, made from impressions taken way back in June of last year. It was a long wait but definitely worth it. I would not call myself a super-expert in custom ear mold IEMs, but I do a lot of headphone listening (HD580 Jubilee, mostly) and I've had various earbuds, from cheap Apex units up to good, generic-fit Westones. Dale got me set up at the show to check the fit and see what I thought of the sound.
I would agree with the above comment - these have plenty of bass, even with the bass ports all the way closed. They have plenty of detail, too, but definitely do not have any zing. I'm not a huge fan of hyped HFs and these suit me really well. The detail and soundstaging is the best I've heard from *any* playback system to date. With just a hair of eq, taking out for me what I would call "just a tad extra mids" these things sound spectacular. Transients are amazing, and the bass really is something to behold.
So far, I've listened to Patricia Barber, some symphonic and string quartet literature, solo piano, Lady Gaga (Bloody Mary sounds INSANE), and some Green Day. One comment is that these don't sound their best when used with a stock iPhone output (duh) but really shine with a decent amp. At home I listened to them with a USBPre from Sound Devices.
I'm completely blown away with these and I have a feeling I'll not be looking around for anything else for a while. The company I work for, Lectrosonics, makes a wireless monitor system (the Quadra) so I was listening to the AS1b with our system. It's a great match so I will heartily recommend these IEMs for any customer who asks.