I have been using the Sabres for almost 2 weeks now. I don't know if they are the panacea for dynamic IEMs, but for the preorder price, they are very good (and as others have mentioned, the accessory bundle is a bit over the top).
They have great authoritative bass without overdoing it too much (though I did find the default red filters to perhaps provide bit too much bass for most music. Not so much that it was too much bass full stop, but that it started to rob detail from other frequencies - I am currently using gold for the most part). As a reference point, the dynamic IEMs that I came from directly were the Vsonic GR07 Classics. The GR07s were a tad bass light, so my initial experience with the Sabres being a bit on the bass heavy side and a tad unrefined or lacking of detail\may be due to me being used to the GR07s (At first, I thought the GR07s were a bit treble harsh and occasionally sibilant when I first got them - but then I began to really appreciate the detail they could offer for a moderately priced IEM). In contrast to the GR07s being a bit more neutral sounding (ie, flatter freq response), bass light, and quite detailed, the Sabres seem more bass heavy, perhaps a bit less detailed, but also with quite a nice smooth/warm character that the GR07s lacked. I wish I could keep both as they are dynamic IEMs with different strengths. Alas, the plastic shell on one of the GR07s has started to develop multiple cracks and I fear - after only using them for 6 months - that its days are numbered. And this is what I really appreciate about the Sabres: the quality metal driver enclosures on an IEM at that price point. What good is the best sounding IEM in the world if it's broken?
My left Sabre also exhibits that clicking/suction cup sound that others are calling driver flex. However, I'm almost positive that this has to due with the ear tips as I can't imaging driver flex being that loud. I will have to double check, but I think this also occurred when I tried another ear tip, so maybe it has to do with how the tip sits on the filter/canal tube?
Edit: Just to add that the clicking sound doesn't happen often enough that it really bothers me. Seems to mostly occur when I am placing it in the ear canal and hardly otherwise.