I've used it a lot and really like it; it would be near the top of my favourites! I've not used it with mats, just on concrete.I've tried both full muckout and deep littering, in my opinion it needs to be deep littered for the best bed. It is very absorbent, doesn't smell and forms a really solid base. Another big bonus for me is that it rots really quickly on the muck heap.
The flax i had i loved, very easy to muck out and as the above poster said forms a lovely solid bed. I found it dusty however, too dusty for me to use as an asthmatic. I could have just been the brand i used of course.
Dusty during summer when really dry (though OK is damped down now and again). Best used deep or semi deep littered and quick to muckout. Pain in the arse to keep out of wounds.
I used to use it - really rated it - fab stuff. Used to deep litter it so got a fabulous warm and comfy bed. Then took the lot out in the spring. Only stopped using at as I moved to Cornwall and it was harded to get, and those placed that did do it, charged fortune. I think its great stuff and would use it again if the price was right. I used matting at front of box to keep clean and rear 2/3rds were deep litter flax - really worked for me.
I use flax, to get it to bed down don't take out the wet for a couple of weeks just pick out dropping. This allows it to build up a firm base. You then usually find an area that wetter than the rest, I take this out once a week,then take the not so fresh looking bedding and put it in the hole and add a new bale or 1/2 bale to the rest of the bed. If you have banks I put the banks in the middle and add the new bale to the sides, so you do not end up with mouldy bedding in the bank.
I keep my horses at home so it keeps my muck heap small and the allotment holders can not get enough of it.
I have recently been using rape straw, Bliss Basic which seems to be chopped much finer than most of the rape straws and is working as well as the flax.
I've deep littered with hemcore,shavings,pellet mix bed for last 2 winters. I don't have rubber matting & did a proper deep litter bed, eg never digging wet out. It was a fab,deep,warm bed. I topped up with bag of hemcore or shavings every week. Loved the bed but due to needing to cut costs this winter have gone back to straw(which I do love as well) but wouldn't hesitate to use hemcore again.