I have bought two lots from these - they are fairly local (within 40 miles) so I picked mine up. First mats have been down a year in 7 stables and are fab! Just bought the same for my barn, dog house and 3 more stables!!
iv got these ones: http://cgi.ebay.co.uk/Easi-Fit-Rubber-St...=item1e59ea7048
& so far so good (this is the first winter down). They were easy(ish) to lay by myself. The only awkward part was getting the jigsaw edges in, but a bit of washing up liquid & a mallet solved that!
I & numerous other horse owners have had mats from this supplier. They fit together well, are reasonably priced & have had no problems with them.
Don't consider mats that are any thinner than 18mm as they tend to wear & rip under the weight & the twisting & turning od horses in a stable. You may get away with them with ponies but certainly not horses.