This bed proves you get what you pay for! Previously I've only bought cheap, soft beds for my two labradors which end up squashed and flat.  Having read the reviews I bit the bullet and so glad I did, this is a really sturdy, quality dog bed.  Despite them both jumping in it, rolling around, the sides remain upright, think they would stay upright even if an elephant slept in it! 
Yes this is more expensive than the usual bed but it's undoubtedly going to be easy to keep clean and will last far longer.
I bought the large although they both tend to curl up in it, there's plenty of room to stretch out if they want.