I have mixed reviews on cat condos.
It seems to me, cats prefer to use YOUR stuff, no matter what. Such as: when you read a newspaper... what's the first thing your cat does? Sits right square on the page all relaxed, as if the newspaper was created just for him. BUT if you lay out the same size newspaper right next to you and try to move him over to THAT newspaper, he will prefer to be on whichever one YOU are reading.
Same with cat condos; they prefer your bed, your laundry basket, your cushions in the kitchen, your rocker. I bought a cat condo and well, dismantled it and it's now just a carpeted box. I put it in a spare bedroom with a bed on top of it. They don't use the carpeted box; every now and then, Zorro will be found curled in the cat bed sitting on top of the destroyed cat condo.
I do have a floor to ceiling cat tree, not a condo, which gets used quite often, by my monster Hammie. He swings like Tarzen around that thing and takes flying leaps to and fro. The other cats have no real interest in it; they prefer the sofa, cushions, my bed...
Which is fine with me... I like 'em on me.