I bought this bed for my burrow loving mini dachsand because she kept getting tangled up in her blanket.  The concept is great and she was so excited to hop in the very first night.
However, about the 10th day, I noticed the material in the "mattress/bed" part had shifted on the part she slept in each night and literally collapsed to the ground, so she couldn't seem to get comfortable. She would move to the middle, but in the middle of the night would roll "down the hill" and end up stuck between the "cave" and the pad.  She is 10 years old and has back problems, as many dachsunds do.  That was the reason I was willing to spend so much money on this bed.  I wanted a good comfy bed for her.  Now, we are stuck.  I tossed out her old bed because I thought she'd never want or need it after purchasing this one.  She is miserable now and I'm broke.  Very disappointing.