Do you mean the Rosewood ones? My piggies love them more than anything but make sure you buy the large size then the piggies can climb in and out- there've been a few horror stories of piggies getting their heads stuck in the smaller ones!
Mine love them! I get the Haycubes for a treat. They love to chew all the forage inside, make the hole a bit bigger then sit inside and eat them from the inside out. After a while I have to cut the bottom off as it gets all soggy with wee. As @PigglePuggle said make sure you buy the larger size Maddy.
I take the forage out and cut a piece of puppy pad to fit the bottom then put the forage back in. The cube lasts for ages this way as the bottom doesn't get soggy. I refill with hay as and when needed and change the pad every couple of days, Spike and Peanut spend hours making the holes bigger and turning it into a bed. None of my other 4 piggies are interested in them.