Literally, loose ends - the removable cover is a great idea but my kitten likes to remove it herself! I had to get some safety pins to fasten it down so she couldn't.  The plastic seems a smidge flimsy, but has held up OK so far.  I used the screws to hold it onto the windowsill instead of the velcro, since one of my cats is a big 25 pound Maine Coon and I didn't want to chance it.  The kitten loves it; she's on it constantly.  Seems soft enough and durable enough for her to enjoy.  While I'd like to see some minor enhancements to durability and fastening, it's a decent enough product as-is and I wouldn't hesitate to buy it again.