We use rubber mats, and have had them down for 7 months now and they are fantasic.
Winter beds with Flax-a-bed- on top on a semi-deep litter system works wonders for 3 months, then we lift the bed and relay again. Only using 1/4 bale each week to top up.
Now that summer is here, charlie & Zak (a boxwalker) are out most of the time unles really wet, and I like to give them 1 night a week in which they appreciate for a good lie down and sleep.
In the summer no semi deep litter system, just 1/2 bale on a bed made on 1/2 the rubber matting for them to have a bit of extra something to lie on, but the TB Zak lies straight on the mat withour hesitation.
We are very lucky to have very good draining stables so have not lifting them yet as no nasty smells, they are very durable, reduce the risk of slips and grazes which effect concrete, and the time saved mucking out is invaluable when working full time and caring for them both. The beds appear warmer in winter and both boys are very happy with them, also does not wear out shoes which for the boxwalker is a good thing.
I would want to have my horses on rubber matting whereever I was.