They took a tiny bit longer to get here than I was expecting, but that was my fault - I preordered them in February before we sold our house, and then forgot to update my address on the order. Oh well!
They are definitely interesting - the reiner and the Thoroughbred have the exact same (weird-looking) pinto pattern, and all of them have eyebrows (naturally). I've seen a lot of controversy over the eyebrows; all I'm going to say on the matter is that these are based on cartoons, and cartoon animals almost always have eyebrows to help convey emotion.
So anyway. Quality-wise, they're a little sloppy, but that doesn't really surprise me - for $4 a pop they aren't going to put as much effort in as they would on, say, a Breyerfest Stablemate, or a Stablemate Club horse. They really aren't terrible - a ding in the paint here, a smudged eyebrow there. Nothing terribly outrageous.
As for the molds themselves, I selfishly wish they'd have used more molds I collect, as I'll only be keeping five of these. But, who knows - maybe there'll be more Stablemates from this series in the future. I have little to no interest in the rest of the releases Breyer put out for this show (which I haven't bothered to watch yet), so hopefully we get more Stablemates in the future.