My cat loves every feature.  She has several cat-friendly scratching devices around the house but she uses the multi-level scratching posts almost exclusively now (allaying the temptation to claw the corner of my sofa!).

Of course she took to the nook bed right away. It took her a few days to venture up to the top-most perch/bed (the feature that was the deciding factor for me) and now it's her favorite place to curl up.  

Very easy to assemble which is fortunate because instructions were virtually non-existent.  But I repeat...VERY easy to assemble.  It did have an odor (glue?) when I first took it out of the box, but I let it air outside for a bit and I don't notice it anymore. 

I highly recommend the Kitty Mansion.  It was reasonably priced, easy to assemble and my cat loves it.  What else is there?