I have all three. They do the thing they are designed to do very well.
The Mary Cries Comp does exactly what PRSh described - you don't know it is on until you turn it off - then you feel the lack of "fullness". So it doesn't pump or artificially squish your signal in an obvious way, but boy does it contribute to a better sound, especially for single coils. IMHO.
The Horsemeat is a very versatile dirt/overdrive, that can be used subtly, to get the kind of push you might get from a Klon-type OD (I am not claiming it is exactly that, just in that "class", shall we say). But it also can be cranked and get quite Boss HM-2 like, and the controls give you a lot of room to play.
The Wind Through the Trees is great for a whole bunch of chorus, univibe, and flanger type effects, and the dual oscillators can really get things wobbling. I use it in a couple of different ways regularly, and quite enjoy exploring all the swirly sounds you can get out of it.
They are quite well made, physically, and aren't noisy.
The MAP pricing for them is a bit high, though not far from other boutique pedals. The used market seems to have some good deals, and you can get a free one this summer through a buy-an-amp-get-a-pedal campaign that PRS is offering.
I fear that these three will be the only three ever released - I don't think the market is ready for PRS pedals, yet, unfortunately. But if they released more, I'd buy them.