the one on the left is the oldest. I recarpeted the center post because it was worn to the wood. The cats really love that the perches are large.
the one in the middle is good too. they like the little house on the bottom sometimes but they like the two tallest beds best. (they are bigger than the lowest bed)
the one on the right I built. The perches turned out a little small but the cats use it anyway.
my cats prefer the sisal for scratching and the carpet as their second choice. they do not (yet) scratch on the wood log.